50A, four pole, double throw relay. 120V, 3 wire or 240V, 4 wire compatible. Can be used to transfer two separate shore/generator circuits. Hard wire installation. Transfer time delay is adjustable from 2 seconds to 10 minutes, which allows the generator to warm up and stabilize before connecting to a load. The Auto Interlock IV is set at 24 seconds from the factory, please specify when ordering if modifications are required.