This fuse is used on the circuit board of many Rheem, Ruud, and Weatherking models. The fuse protects the low voltage transformer in the case of a short circuit or overload in the low voltage components, thermostat, or wiring. These fuses are sold in a package of 5 fuses. This fuse replaces Rheem Ruud Weatherking part numbers 44-ATC3 and 44-24351-01.