Fireboy-Xintex 3 Circuit Engine Shutdown w/Square Display3 Circuit Engine Shutdown with Square Display Designed for low current, electronically controlled engines. Featuring sealed relays with gold plated contacts and is guaranteed to operate in all electronic engine applications. Engine circuit relays feature an operating range of 10 A to 2 amps. Auxiliary relays have an operating range of 100 mA to 10 amps for the shutdown of generators, dampers, louvers, and other types of related engine room equipment.