Zerostart 2204037 Circulation Heater, 5/8" Diameter Inlet/Outlet | CSA Approved | 120 Volts | 1500 Watts Thermostatically controlled: Opens at 190 Degree F, closes at 151 Degree F Vertical installation only Rugged cast aluminum construction is corrosion and impact resistant Copper heating element provides excellent heat transfer Dimensions: 2-3/4" x 8-1/2" (7cm x 21.6cm)