Boat owners, listen up - these trailer rollers from MAMDAFAON will make your life so much easier. The kit includes a 4-inch bow roller, two end bells, and a 1/2 inch diameter bolt - everything you need for a complete installation that's about 7-1/4 inches wide total. The rollers are made from thermoplastic polyurethane elastomer (TPU) which is this tough, flexible material that won't rust and won't leave marks on your boat's finish. They're designed to support your boat's weight properly while absorbing road shocks during transport - way better than those hard plastic rollers that transfer every bump. The end bells are genius too - they prevent your boat from scraping against the bolts or bracket, so no more annoying scratches. Installation is straightforward and once it's on, you'll notice how much smoother loading and unloading becomes. Perfect for keeping your boat secure during transit and making your launch and retrieval process way less stressful. MAMDAFAON focuses on boating comfort and safety, and these rollers deliver exactly that. Your boat (and your peace of mind) will thank you!