Heat only line voltage thermostat, offers 5/2 day programmable settings for baseboard, cable and ceiling heat. pre-programmed: 4 periods per day, temporary override and manual hold, selectable fahrenheit/celsius setting, adjustable teperature swing (differential), positive on/off switch, optional wall plate, easy to read display, easy to use, ul approved, requires 2aa alkaline batteries. for use on: 1 stage heat only: single or double pole, 120/240 vac systems up to 15 amps, hydronic (hot water) systems with motors up to 1/4hp, 120v: 1,800 watts (resistive)/ 240v: 3,000 watts (resistive).