Zone Panel, 4-Zone, Expandable, TrueZone®, 3 Heat Stages, 2 Cool Stages, Temperature Setting: -40 to 165 Deg F, Terminal Designation: Four of M1, M4, M6, R, C, W1/E, W2, W3, Y1, Y2, G, O/B, L One of RH, RC, W1/E, W2, W3, Y1, Y2, G, O, B, DS/BK, R, C, AZ1, AZ2, OT, DATS, LED Display, 24VAC Power Source, 18 to 30VAC Voltage Rating, Wall Mount, Gray, 13-1/2 inch Height, 8 inch Width, 2 inch Depth, Standards: FCC Class B, For Use With: THM4000R1000 Wireless Adapter, Programmable and Non-programmable Thermostats , 50/60 Hz Frequency, Humidity Range: 5% to 90% RH Non-Condensing