Honeywell The Round Mercury Free Thermostat T87K1007, With Manual Changeover Rwy

The round mercury free thermostat w/ manual changeover rwy the round mercury free thermostat w/ manual changeover rwy has a manual changeover and can heat conventional systems and heat pumps with no auxiliary heat. features battery assisted power stealing, 24v heat only 40-90f, and relay switch. color finish is premier white.