ProMelt® ContractorPro™ Panels control systems of any size with a compatible ProMelt Control. ContactorPro panels are available in 50, 100 and 200 Amp models to operate systems with 120, 208, 240 or 277 VAC power. A built-in 24 VAC transformer provides power to the connected control. Each NEMA Type 1 panel measures 12 in x 12 in x 4 in (w x h x d) and includes knockouts for conduit.