This product has been discontinued.
Extech RH522  

RH522: Humidity and Temperature Probe For Extech RH520 Paperless Chart Recorders

The RH522 is a replacement Humidity Temperature Probe for Extech Paperless Chart Recorders. -20 to 140°F (-28 to 60°C) Temperature and 10 to 95% RH ranges. No calibration required. For use with models RH520A, RH520A-220, and RH520A-240.