Best Langkou in 2026

Indoor CO2 Monitor: Compact size Body with hollow back design for carring and airflow. Big colorful LCD digital screen for people easy to identify and read. Not only monitoring the CO2 content, also can test the temperature & humidity. Air quality monitor is Keeper of family health, Perfect for home interior, such as living room, baby room, classroom, office and which closed places etc.

Necessity of Air Quality Monitor: Carbon dioxide (CO2) is not harmful to human body when it is low, but when it overs a certain amount, it will affect the breathing of humans (and other organisms). If serious, life is threatening. Thus, we have to monitor the CO2 content of air for keeping health.

Advanced NDIR Technology: Mini CO2 meter uses high precision NDIR sensor technology to detect carbon dioxide content accurately and quickly. and it can hazard assessment, when CO2 of air exceed the setting alarm value(alarm value: 1000 PPM), it will warn to remind people to open the window or turn on air purifier for keeping balance of air.

Professional Voice Device - It is a high quality recording and noise reduction function that can record high quality sound for you, helping you to capture the speaker's words in interviews, speeches and conferences, so you won't miss the highlights.

Easy to Use & Simple Design - One button operation ensures you won't miss any important information. Press "REC" once to record, and then press "STOP" once to save. Each recording is time-stamped for easy location of your files. Multi-platform compatibility allows you to use our device on any platform and supports external sound speaker playback, so you can enjoy superior recording quality.

Large Capacity Recorder - This recorder has plenty of memory, enough space for 30 hours of recording. It can also be used as an MP3 player/music player, allowing you to relax while studying

【Set Contents】Recorder*1, 64GB TF card*1, 3.5mm headphones*1, Micro-USB cable*1, manual*1. Product Dimensions: 3.54 x 1.26 x 0.47 inches; Item Weight: 5 ounces

【1536kbps → 3072kbps Upgraded HD Recording】Our 64GB audio recorder adopts the latest PCM ten-core triple digital intelligent noise reduction technology, providing a steady performance and a clear recorded voice. Equipped with exclusive omnidirectional stereo microphone and DSP dynamic noise cancellation recording chip, which can capture farther/lower but clearer sound.

【64GB Large Capacity】📂 Voice recorder is equipped with a large capacity of 64GB, which is three times the memory capacity of similar products on the market. Store up to 750 hours of recording files to meet your various recording needs. 250mAh rechargeable battery supports up to 20 hours of continuous recording and 12 hours of headphone playback. Support recording while charging, and has data protection function, automatically save when the battery power is low.

【Simple Operation & Local Playback】Say goodbye to complicated operations, 4s fast recording, without missing any details. Built-in speakers can play recordings directly. (The effect will be better with headphones)

【64GB Large Capacity】📂 Voice recorder is equipped with a large capacity of 64GB, Store up to 272 hours of recording files (512kbps) to meet your various recording needs. 🔋 370mAh rechargeable battery supports up to 33 hours of continuous recording. The included Type-C cable connects to your computer for high-speed data transfer.

【Dual Microphone & DSP Noise Reduction 】2 high-performance 360 ° directional microphones, which can more clearly capture sounds in the distance. Powerful DSP noise reduction chip, intelligent digital noise reduction, it can automatically reduce environmental noise, clear recording/playing high-quality sound. The supported bit rate is 3072kbps/1536kbps/512 kbps.

【Voice Recorder PCM 1536kbps Recording】Langkou Voice Recorder With the latest PCM deca-core triple digital intelligent noise reduction technology(DSP), it can provide you with high quality sound at 1536kbps, as if the person speaking is standing next to you. Equipped with an exclusive omnidirectional stereo microphone that captures farther away but clearer sound.

【One-Touch Recording】Super easy step-by-step recording, perfect for recording beginners. Turn the power switch on and record/save with a swipe of a button in standby, never miss an important message again!

【64GB Large Capacity in Memory】Langkou 2023 upgraded recorder has a built-in 64GB TF card expansion memory and the 64GB digital recorder can store up to 776 hours of recording files (192kbps). 270mAh rechargeable battery supports up to 12 hours of continuous recording and 24 hours of headphone playback. It is a professional recording device that fully meets all your recording needs！

The perfect companion for indoor environments, allowing you to monitor CO2 levels, temperature, relative humidity, and atmospheric pressure in real-time

Easy for anyone to use – the color coding and the optional buzzer warns you when the CO2 concentration gets too high

Power-efficient e-ink display ensures super long battery life for this wireless device (up to 4 years)

RELIABLE RADON RESULTS: As radon levels fluctuate daily, continuous long-term measuring is necessary. Airthings Wave Plus measures radon accurately and reliably

CLEAN AIR SENSORS: Radon, Carbon Dioxide (CO2), VOCs (airborne such as kitchen gases, fumes and cleaning products), humidity, temperature and air pressure sensors allow you to gain full visibility into six key indoor air factors

EASY AND CLEAR RESULTS: Connect via Bluetooth to the Airthings App or log in to the Airthings Dashboard online for detailed insights into your air

Fully customizable ppm deadband and CO2 set point allow flexibility in programming

Trend chart records CO2 levels per minute, hour, day and week for accurate analysis of CO2 distribution

Adjustable trend chart zoom levels let you trace your ppm levels

⚛️ ACCURATE: Carbon Monoxide (CO) gas detector, 0-1000ppm with 1ppm resolution. USA NIST Calibration. Turn ON and GO.

🌇 DETECT: Electrochemical cell sensor with error better than ≤±5% F.S. and response time: T<30s. Zero and span calibration options. Comes factory calibrated.

🎆 ALARMS: Adjustable audio, visual, and vibration alarms alert when preset levels are reached. Alarm digital time stamp and logging.

🏕️ [High-precision CO2 Sensor]: The CO2 detection adopts the most advanced sensor of Swiss Sensirion's unique PASens technology, and adopts the photoacoustic detection principle to perform accurate and reliable measurements in a wide range of concentration areas and applications.

🔔 [Carbon Dioxide Concentration Alerts]: The CO2 concentration alert value can be customized to make our life, work or production environment safer.

💧 [Temperature and Humidity Monitor]: Temperature and humidity are closely related to human body, plants or storage environment. This air quality tester has the function of real-time monitoring of temperature and humidity.

✅ [PROTECTS EVERY BREATH] – When it comes to the health of your family, AirKnight knows that every breath counts. Our 9-in-1 air quality monitor is equipped with powerful sensors that detect the main 8 kinds of air pollution (CO2, VOCs, Formaldehyde, AQI, PM2.5 & PM10 Dust Particles, & more) in REAL-TIME, all displayed on one sleek, clear LCD screen.

✅ [SIMPLE, FAST SETUP] – No complicated app, badly written instructions or Wi-Fi required for one of the most premium indoor air quality meters. Our device was specially designed to be operated by anyone, anywhere, so you can keep your space safe without a tech-induced headache. An instructional video is included also, just in case.

✅ [PORTABLE FOR EVERYWHERE, ANYTIME USE] – Featuring a heavy-duty 3000 mAh rechargeable Lithium-Ion battery, your AirKnight AK1000 portable air quality monitor is designed to travel with you, monitoring your air quality for hours at a time on a single charge. Never go unprotected again!

Indoor CO2 Monitor: Compact size Body with hollow back design for carring and airflow. Big colorful LCD digital screen for people easy to identify and read. Not only monitoring the CO2 content, also can test the temperature & humidity. Air quality monitor is Keeper of family health, Perfect for home interior, such as living room, baby room, classroom, office and which closed places etc.

Necessity of Air Quality Monitor: Carbon dioxide (CO2) is not harmful to human body when it is low, but when it overs a certain amount, it will affect the breathing of humans (and other organisms). If serious, life is threatening. Thus, we have to monitor the CO2 content of air for keeping health.

Advanced NDIR Technology: Mini CO2 meter uses high precision NDIR sensor technology to detect carbon dioxide content accurately and quickly. and it can hazard assessment, when CO2 of air exceed the setting alarm value(alarm value: 1000 PPM), it will warn to remind people to open the window or turn on air purifier for keeping balance of air.

Measuring Range CO2: 0~9999ppm

Temperature Range: -10.0~60.0°C (14~140°F) /Resolution: 0.1°C/°F / Accuracy: ±0.6°C / ±0.9°F

CE Marking, passed the standards and had been approved by European Directives for health & safety

MULTIFUNCTIONAL & SCIENTIFIC – This indoor air quality monitor accurately assesses temperature (in C/F), humidity level, and multiple measures of air quality including concentrations of formaldehyde, total natural & synthetic volatile organic compounds causing most odors (TVOC), and fine particulate dust matter (PM2.5/PM1.0/PM10) which travel deeply into the respiratory tract, reaching the lung alveoli.

PORTABLE TESTING – Spot check or leave device on for continuous monitoring of indoor air quality. Built-in stand allows air monitor to be placed unattended anywhere. This easy-to-carry device can help monitor air quality at home, in the car, and in hotel rooms. The lithium battery provides portable power when DC 5V micro USB charging is not available. Information is displayed on a clear 2.8” 320 x 240 pixel color LCD display.

ADVANCED FAN & SENSORS – This air quality monitor has a built-in fan to quickly draw in ambient air to allow REAL-TIME measurements. It incorporates a laser sensor to measure levels of dust particles and has a second electrochemical semiconductor sensor to measure formaldehyde and natural/synthetic organic compound levels. Air monitor also auto calibrates in fresh air.

MULTIFUNCTIONAL & SCIENTIFIC – As our newest model, this indoor air quality monitor accurately assesses temperature in Celsius, humidity level, and multiple measures of air quality including concentrations of formaldehyde, total natural & synthetic volatile organic compounds causing most odors (TVOC), and fine particulate dust matter (PM2.5/PM1.0/PM10) which travel deeply into the respiratory tract, reaching the lung alveoli.

PORTABLE TESTING – Spot check indoor air quality anywhere or leave device on for continuous monitoring. This easy-to-carry air quality tester can help monitor air quality at home, in the car, and in hotel rooms. The lithium battery provides portable power when DC 5V micro USB charging is not available. Information is displayed on a clear 2.8” 320 x 240 pixel color LCD display.

ADVANCED FAN & SENSORS – This air quality monitor has a built-in fan to quickly draw in ambient air to allow REAL-TIME measurements. It incorporates a laser sensor to measure levels of dust particles and has a second electrochemical semiconductor sensor to test air quality including formaldehyde and natural/synthetic organic compound levels.

MULTIFUNCTIONAL & SCIENTIFIC – This indoor air quality monitor accurately assesses multiple measures of air quality including concentrations of formaldehyde (HCHO), total natural & synthetic volatile organic compounds causing most odors (TVOC), and fine particulate dust matter measuring <2.5 microns in size (PM2.5) which travel deeply into the respiratory tract, reaching the lung alveoli and can worsen asthma.

PORTABLE TESTING – Spot check indoor air quality anywhere or leave device on for continuous monitoring up to 2 days. This easy-to-carry air quality tester can help monitor air quality at home, in the car, and in hotel rooms. The 2200mAh battery provides portable power when DC 5V micro USB charging is not available. Information is displayed on a clear 2.8” color LCD display.

ADVANCED FAN & SENSORS – This air quality monitor has a built-in fan to quickly draw in ambient air to allow REAL-TIME measurements. It incorporates a laser sensor to measure levels of dust particles and has a second electrochemical semiconductor sensor to measure formaldehyde and natural/synthetic organic compound levels.

[7-IN-1 Multifunctional]: This professional air quality monitor measures CO2, PM2.5, PM10, particle numbers, HCHO, temperature and humidity.

[Advanced Built-in Sensor]: Equipped with Temtop Laser PM2.5 sensor, SenseAir NDIR CO2 sensor, Dart electrochemical HCHO sensor and Sensirion temperature and humidity sensor.

[Audio Alarm]: The monitor will automatically alert through the built-in buzzer (MUTE function available) and the indicator light when the air pollution levels get too high.

【Award-winning Multifunction Air Quality Detector】Qingping Air Monitor shows a full picture of Indoor Air Quality (IAQ) by monitoring PM2.5, CO2, TVOC, temperature, and humidity. It provides real-time data of weather forecast, AQI, and UV index (forecast of AQI and UV is not available in the US). You can also check the date, calendar and time on the screen (need to connect it to the network to access the right time zone). The product with elegant design has won an iF and a Red Dot design awards.

【Accurate and Reliable Measurement】The product is fast-responding and sensitive with a 1.2GHz 4-core A7 chipset. The product has top-level sensors built-in, along with the multi-mode compensation algorithm, the measured data is accurate and reliable. The innovative design of the vents enables sufficient contact between the air and the sensors to improve efficiency. The evaluation and colorful bar under readings help you to interpret the indoor air quality.

【High-resolution Touch Screen】The 3.1'' IPS touch screen with 328 PPI is ultra-clear. The brightness can be adjusted automatically. Each metric is with a color indicator under the number, so you can understand the indoor air quality and the temperature/humidity level of your room at a glance. You can touch the numbers or slide to switch the interfaces, all the operations are smooth and easy.

Acrylic clear case shell, high transmittance to be looked through

2.8" TFT screen, colorization display, wide angle vision up to 180°

High sensitivity sensor ensures the high accuracy in data collections

ALWAYS-ON AIR QUALITY SENSORS: WiFi connected indoor air quality monitor measuring radon gas, particulate matter (PM2.5), carbon dioxide (CO2), VOCs (airborne such as kitchen gases, fumes and cleaning products), humidity, temperature, and air pressure.

ACCURATE DIGITAL RADON DETECTOR: Radon is the number one cause of lung cancer among non-smokers and kills more than 6x the number of people than home fires and carbon monoxide poisoning combined.

FREE & FRIENDLY APP: Use the Airthings app to manage notifications, check current readings, and analyze trends over time. Check your local pollen forecast.

Multiple Detectable Gases - BIAOLING upgraded indoor air quality monitor built in DART electrochemical sensors that can accurate detect air of Carbon Dioxide(CO2), Formaldehyde(HCHO), Volatile Organic Compound(TVOC), Particle Matter(PM2.5/PM10). This new mode can offer real time data and mean value, it is recommend you to focus on mean value of each gas after testing enough time because long-term monitoring, the real-time data exist instability.

Know Your Air Clearly - For everyone,It's necessary to know the air quality of the place where you live.This air monitor have LCD Digital Color Screen, large and easy to read. This air monitor will offer color indication to show overall environment quality which have Good(Green), Mild Pollution(Yellow),Severe Pollution(Red) three grade. You can directly to know the overall environment quality and track on each gas mean value to know what gas in air is unsafe and take accordingly actions.

Easy Operate - This air monitor is easy to operate which just pressing the functional button and one full page design make everyone can easy to read all the real time readings at the same time. Size about 5.83” * 2.76” * 1.18”. It's easy to carry the intelligent air quality monitor that can help us detect the air quality in household, kitchen, bedroom, office, school, car, hotel, travel, camping, party etc...especially in which has baby,child and pregnant woman.

The economical 5-in-1 air quality detector use highly accurate and professional sensors to measure PM2.5, PM10, particle, HCHO and AQI.

By using our latest 3rd generation Temtop laser particle sensor and optimised PSO algorithm, it makes particle measurements become more accurate and stable and enhanced its sensor life up to 20,000 hours.

The pre-factory calibrated electrochemical sensor enhanced its accuracy and capturing formaldehyde molecules more precisely.

Multiple Detectable Gases - BIAOLING upgraded indoor air quality monitor built in DART electrochemical sensors that can accurate detect air of Carbon Monoxide(CO),Carbon Dioxide(CO2), Formaldehyde(HCHO), Volatile Organic Compound(TVOC), Particle Matter(PM2.5/PM10). This new mode can offer real time data and mean value, it is recommend you to focus on mean value of each gas after testing enough time because long-term monitoring, the real-time data exist instability.

Know Your Air Clearly - For everyone,It's necessary to know the air quality of the place where you live.This air monitor have LCD Digital Color Screen, large and easy to read. This air monitor will offer color indication to show overall environment quality which have Good(Green), Mild Pollution(Yellow),Severe Pollution(Red) three grade. You can directly to know the overall environment quality and track on each gas mean value to know what gas in air is unsafe and take accordingly actions.

Easy Operate - This air monitor is easy to operate which just pressing the functional button and one full page design make everyone can easy to read all the real time readings at the same time. Size about 5.83” * 2.76” * 1.18”. It's easy to carry the intelligent air quality monitor that can help us detect the air quality in household, kitchen, bedroom, office, school, car, hotel, travel, camping, party etc...especially in which has baby,child and pregnant woman.

ALL-IN-ONE RELIABLE AIR QUALITY MONITOR. The most advanced monitor measuring particulate matter (PM2.5 and PM10), formaldehyde (HCHO), VOC (airborne chemicals), humidity, temperature, and AQI. Tested by AQMD, R2 up to 0.999.

DATA EXPORT AND HISTOGRAM. The histogram function can reflect the changes on PM2.5 directly for the latest 12 hours, helping you to keep track of the air. Export data to gain full visibility and analysis into 7 key indoor air factors. Memory allows at least 3 months of continuous data recording.

PRE-CALIBRATED SENSORS. The pre-calibrated Dart electrochemical sensors will accurately capture formaldehyde molecules accompanied by the detection function covering a wide range of organic pollutants.

UPGRADED SENSOR: Adopting Temtop second-generation PM2.5 particle laser sensor, directly transform the PM2.5 & PM10 concentration into visual data and colorful health level indicators, providing an effective safeguard for you and your family.

PROFESSIONAL SENSOR: Advanced industrial-grade sensor offers more than 20,000 hours lifespan. Combined with the unique particle swarm optimization algorithm, it makes particle measurement more accurate and stable.

DATA GRAPH: Large storage capacity to store and display the data of the past 12 hours, check the air status via the histogram and track the trend of air quality for the specific time period.

Know Your Air: this air quality monitor provids accurate PM2.5 information(with high quality Series Particle Sensor) in your home/office and allows you to take timely measures to keep the air quality within safe levels

3-in-1 Multifunctional Tester: displays PM2.5/AQI current and max value for 1h/24h/since last reset; also measuring the indoor temperature(°C/°F switchable) and relative humidity； Note: No outdoor temperature and humidity; will not detect mold

6 Grades Air Quality Levels Indicator: Good, Moderate, Poor, Unhealthy, Severe and Hazardous, showing you instantly what your air quality is like

Latest Generation of Formaldehyde Air Rapid Test Kit for home, office, automobile etc. indoor air quality test.

Rapid and semi-quantitative testing of air formaldehyde without the need for any equipment.

Great for on-site testing of formaldehyde inside a car, a room or furniture.

【Multifunctional Indoor Air Quality Monitor】 This indoor air quality monitor accurately assesses intemperature & humidity level, and multiple measures of air quality. Including concentrations of formaldehyde (HCHO), natural & synthetic volatile organic compounds (TVOC), fine particulate dust matter (PM2.5/PM1.0/PM10)

【Portable Testing】 Just pressing the power on/off button, keep the device turned on and it will take the measurement automatically. The lithium battery provides portable power, standby time can last for 6-8h (supplied with USB cablea and charger). Small and lightweight, weight is only 170.5g, help monitor air quality at home, in the car, and in hotel rooms. Design with LCD color screen digital display, you can see all the information clearly.

【Innovative Technology】 This indoor air quality monitor has a built-in fan to quickly draw in ambient air to allow real-time measurements. It incorporates a laser sensor to measure levels of dust particles and has a electrochemical semiconductor sensor to test formaldehyde and natural & synthetic organic compound levels.

Accurate Detection: This square air quality monitor can accurately detect and display the levels of key pollutants in your indoor environment, including PM2.5, TVOCs, formaldehyde, and more.

Real-Time Monitoring: With real-time monitoring, this air quality monitor provides you with up-to-date information on the air quality in your home or office, helping you make informed decisions about ventilation and air purification.

Portable Design: The compact and lightweight design of this air quality monitor makes it easy to move from room to room or even take with you on the go, ensuring that you always have access to accurate air quality readings.

Portable Formaldehyde HCHO , TVOC Gas Concentration Detector with 3 Colors Light (Green/Yellow/Red) Alarm for Indoor home safety

Formaldehyde HCHO / TVOC Range : 0 ~ 9.999 mg/m3 ; Resolution : 0.001 mg/m3 ; Sensor Type : Semiconductor

Built in 360 degree detector ports on top of the meter , LCD Display HCHO / TVOC Data with Blue Color Back lighting