Product Details Ⅰ. Carbon dioxide monitoring for indoor air quality, supporting maintenance of a healthy environment with low carbon dioxide concentration Ⅱ. High precision measurement with reference accuracy in the specified range of 400 - 2000 ppm and accuracy of ± (40 ppm + 5%) Ⅲ. On - chip temperature and humidity compensation via built - in sensor for reliable measurements Ⅳ. Intelligent regulation of indoor ventilation system based on carbon dioxide concentration Ⅴ. Low power operation with average current less than 0.4 mA @ 5 V when measuring once every 5 minutes Specification Ⅰ. Material: PC + Metal Ⅱ. Colour: Blue Ⅲ. Supply voltage range: 2.4 - 5.5 V Ⅳ. Interface: Digital I2C (SCL: I2C clock port, SDA: I2C data port) Ⅴ. Pin interface spacing: 2.54 mm Ⅵ. Interface definition: 1. GND (negative input port of power supply), 2. Positive input port of power supply, 3. SCL, 4. SDA Package Contents Ⅰ. 1 x sensor module Warm Tips Ⅰ. Light reflection and different displays may cause slight colour difference between the item in the picture and the real thing Ⅱ. The measurement allowed error is +/- 1 - 3 cm