Installing an LED light bar on your truck, Jeep, or ATV? You NEED this wiring harness kit! It's not just some random wires - this is a complete 40A relay harness with a fuse, on/off switch, and all the connectors you need for a proper, safe installation. Fits LED bars from 18W all the way up to 100W from major brands like CREE, Philips, EPISTAR, and OSRAM. The 12V system is standard for vehicles, and the 40A relay handles the high current without melting. Comes with 4 leads for easy connection to battery, switch, and lights. Part number W03-LED-LIGHT-BAR-RELAY-KIT from XDR9 brand. Performance/custom fitment. Brand new in packaging. Using this harness instead of rigging something up yourself prevents electrical issues, protects your vehicle's system, and makes the install look professional. Seriously, don't just hook wires directly to your battery - do it right with this kit. Your lights will work better and last longer!