The WarmlyYours SCM-DUAL Snow and Ice Melting Timer Control is a simple, affordable option for snow melting, slab heating, and roof and gutter deicing systems. At 120V operational voltage, this unit features a 12-hour, adjustable timer and a NEMA 1 enclosure with hinged cover. The operation of this control couldn’t be easier as the user can simply turn the timer to their desired heating duration. It includes a 2-pole relay and terminal block for easy wiring. For projects with a smaller amperage draw (20 Amps for 120V or 10 Amps for 240 – 277V), the SCM-DUAL can be used without a relay panel. However, for projects with larger amperage draws, the controller must be used with a compatible relay panel. Using a relay panel, sold separately, allows control of larger jobs and can help switch voltages ranging from 120V to 277V.