Single Stage Universal (1H/1C, or 1H, or 1C) Horizontal Setpoint Thermostat, 24 Volts, Snap Action Contact, System Switch-Heat, Off, Cool, Fan Switch-Auto, On, Profile-Horizontal, can be used on 3 wire zone valve and 750mV applications, Includes Heat/Coolonly Terminal Wallplate, Range 50-90° F, Terminals-RC,RH,W,Y,G,O,B,A. (MERCURY FREE)