The Terma SIM Element has one fixed internal operating temperature of 65°c. Element will thermostatically operate to maintain this temperature. No Timer. Compatible with external Timer. 26mm length from thread down. 345mm internal probe length. No power button on element itself. Operable from the switch fused spur. Straight cable, no plug. IP67 (safe for use in bathroom). Class 1. Wattage Selection Advice: To correctly choose the right wattage of element for your towel rail or radiator, you should look at the output of the chosen radiator as central heating (hydronic) in watts and choose an element with the wattage closest to that figure. If the output of the chosen radiator is only listed in BTUs, the conversion formula is BTUS / 3.41 = Watts. Electrification Advice: When electrifying any radiator check it is suitable to work with a heating element. Dual Fuel Advice: If you are buying a heating element to convert a towel rail for use as dual fuel it is important to remember to regularly bleed it as air can build up inside. A heating element should never be run in the open air as this could potentially cause the surface of the rail to get extremely hot and burn your towels.