Easily manage and control your 12V accessories with the MB Quart GMR-RB4 4-Circuit 20 Amp Relay Bank, designed for seamless integration and simple setup. Built for use with the GMR7V1 Source Unit (sold separately), this relay bank delivers powerful plug-and-play capability, giving users full digital control of up to four separate 12V circuits. Ideal for marine, off-road, or custom vehicle applications, the GMR-RB4 offers a reliable and professional-grade solution for powering lights, pumps, fans, or any other 12V accessory with ease.Installation is straightforward with a simple three-wire connection. Just plug the included male JST connector into the GMR7V1’s ‘AUX TRIGGER’ port, then provide 12V power and ground via an 8 AWG wire (80A fuse required on the power wire). Each of the four independent circuits supports up to 20 amps max, offering plenty of power for a wide range of devices. Connecting accessories is quick, with clearly labeled terminals and simple 12V power/ground wiring.What sets the GMR-RB4 apart is its built-in LED fuse indicators—a glowing red light instantly identifies a blown fuse while the circuit is still loaded, taking the guesswork out of troubleshooting and ensuring quick, hassle-free maintenance. Whether you're adding off-road lights, air compressors, or audio components, the GMR-RB4 is your all-in-one solution for safe, clean, and efficient 12V power distribution. Get total control and a streamlined installation with the MB Quart GMR-RB4 Relay Bank—built for performance and engineered for simplicity.