Honeywell Round™ Thermostat, Manual, Series: T87N, Non-Programmable Thermostat, Relay Switch, R, RC, W, Y, G, O, B Terminal Designations, Heat/Cool/Off System Switching, Auto/On Fan Switching, Thermistor Sensor, 1 Stage, 5 to 90 % Humidity, 20 to 30 VAC, Round Mounting, Premier White®, 3-11/16 in Dia x 1-3/4 in D, Import