CURT add extra safety and visibility to your vehicle when towing a cargo carrier, bike rack or other hitch-mounted accessory. Simply stick them on, using the included 3M adhesive backing. These LED cargo carrier lights easily plug into your vehicle’s standard 4-flat connector and synchronize with the taillights, brake lights and turn signals. CURT LED indicator lights are constructed to be durable and waterproof to long outlast the elements.