Adafruit HTU21D-F Temperature & Humidity Sensor Breakout Board [ADA1899] HTU21D-F Temperature & Humidity Sensor Breakout Board i2c digital interface (7-bit address 0x40) 3.3V voltage regulator and i2c level shifting circuitry on board Operating Voltage: 3.3 to 5V (Power and logic level) Dimensions: 18mm x 16mm x 2mm / 0.7" x 0.6" x 0.08" Weight: 1g