The Winland EAPRO-WHS EnviroAlert Wireless Humidity Sensor (EAPro Wireless Humidity Sensor) is a wireless humidity sensor to monitor ambient room humidity communicating to the EAPro Gateway as a part of the Winland Critical-Environment Monitoring Solution. Winland EAPRO-WHS EnviroAlert Wireless Humidity Sensor Main Features Indoor transmission distance of 500' (152.4m) - (results may vary) Set humidity high/low set points on EnviroAlert Professional Gateway (local). Monitor/adjust locally or via INSIGHT (remote, sold separately) Do NOT place EAPro-WHS into cooler/freezer environments. Use a wired sensor. Sensor monitoring humidity range of 5 to 95% RH with accuracy of ±5% 2.405GHz - 2.479GHz, 7 channels Power requirements of two AA alkaline batteries and/or 12V DC transformer. See "Winland Battery Life Statement" for recommendations. Unit operating range of 32 to 122 F (0 to 50 C) in non-condensing environment Surface mount Dimensions of 3.9" x 2.9" x 1.7" (9.9cm x 7.4cm x 4.3cm) Weight of 3.3oz (93.5g) without batteries / 4.9oz (138.9g) with batteries