The Winland EAPRO-WMFT EnviroAlert Professional Wireless Multi-Function Transmitter (EAPro Wireless Multi-Function Transmitter) is a wireless transmitter used with sensor (sold separately) to monitor and communicate to the EAPro Gateway as a part of the Winland Critical-Environment Monitoring Solution. Main Features Indoor transmission distance of 500' (152.4m) - (results may vary) Wireless Multi-Function Transmitter requires accessory sensor for operation. Maximum sensor cable run of 1,000' (304.8m) [18-22 twisted pair] from Wireless Multi-Function Transmitter Do NOT place EAPro-WMFT into cooler/freezer environments. Use a wired sensor connected to the EAPro-WMFT Set temperature high/low set points on EnviroAlert Professional® Gateway (local). Monitor/adjust locally or via INSIGHT (remote, sold separately). 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