12 Volt 40 amp 4-prong relays Mechanical life of 10，000+ cycles Heavy-duty impact molded relay socket with 4 WIRES Interlocking relay sockets High 40A coil capacity- able to handle those high current applications with ease Hundreds of uses include- starter kills， domelight supervision， trunk release， polarity change，power door lock/actuator control， change a low current output to high current，add ignition/accessory outputs， control motors/other electronics， It is Also suitable for automobile used for control， alarms， horn， headlight and more....Package include: 1 x 40A replay (4Pin) 1X Relay Socket Wire