Honeywell - Wireless Adaptor allows easy addition of RedLINK enabled thermostats to TrueZONE systems. Use with RedLINK-enabled TrueSTEAM humidification system to communicate and control humidity. Also controls dehumidifiers like Honeywell TrueDRY. Powered by RedLINK reliability. No interference with other wireless devices in the home. Communicates with wireless outdoor sensor to automatically control humidity at proper levels. Dimensions: 5-9/16 inch high x 4-3/8 inch wide x 1-1/4 inch deep (141mm high x 112mm wide x 32mm deep). Mount wireless Adaptor on wall near HVAC equipment or on the duct. Operating humidity range (% Relative Humidity-RH): 5 to 95% RH, non-condensing. Operating temperature range: -40F to 165F (-40C to 73.9C). Color: gray. One Adaptor per zone control panel (HZ322 or HZ432 TrueZONE panel).