Replaces JWB# 6521000, 240Volt, 5.5kW,2 1/4 inch slip ends for couplings, 17 3/8 long. The standard heater for decades for numerous Jacuzzi models. Recently available with replaceable element (not shown). Note picture showing large nut under connection terminals identifying a replaceable element unit. Prior heaters from the 80's-2009 DO NOT have replaceable elements.Two thermowells for sensors, hi-limit included and installed.