HIH7120-021-0011 - Honeywell HumidIcon™ Digital Humidity/Temperature Sensors: HIH7000 Series, I2C, ±3.0 %RH accuracy, SIP 4 Pin, without filter, non-condensing
Datasheet: https://sensing.honeywell.com/index.php?ci_id=147071
Prog: https://sensing.honeywell.com/command-mode-humidicon-tn-009062-3-en-final-07jun12.pdf
Price: 7.22$ Digikey