Generic 30-40 amp relays, recommended to be used for any situation you need to protect a circuit or older motor or switch. Comes with pre-wired harness for easy installation. Organize special projects with high quality relay bank. Configure to your own needs. Includes heavy duty 40 amp relays, expandable housing and color coded hookups. All relays are 12 volt single pole double throw. All wires printed exactly so you know how to wire them. Picture shows only 3 relays, be assured 4 relays will come in a similar configuration with this part number.