Features a circuit breaker on the board to protect 12V circuits from short circuit damage and a short circuit indicator that indicates shorts in wires to the main switch or interior light. Heavy-duty diode trips circuit breaker if the 12V DC is hooked up backwards. Fuses on the 120V AC circuits give you protection from short circuits in the heater wires and element. For use on Dometic old and new style gas valves: RM 663, RM 763, RM1303, RM3500, RM3600 and RM3800