Durable module for measuring temperature and humidity. For ESP and Raspberry perfect for weather stations Due to the tiny size of the sensor, the power consumption is incredibly low, making it suitable for virtually any application. The humidity and temperature sensor board that carries a digital SHT21 humidity and temperature sensor from Sensirion. The SHT21 uses a capacitive sensor elements to measure humidity, while temperature is measured by a band space sensor. Both sensors are perfectly coupled to a 14-bit ADC, which then transmits the digital data via the I2C protocol. It has a 4-pin interface that can communicate directly with the analog pins Bidirectional communication over a single pin on I2C protocol Board is 5V tolerant, allowing sensor to run from a 5V supply on I/O pins size:about 1.3x1cm Material:plastic colour:Blue Package Contents: 10 x HTU21D Temperature & Humidity Sensor Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.