This blue PVC 12-inch skid pad will fit 3-inch width boat trailer crossmembers, and is designed to protect your boat hull from contacting the crossmember when loading and unloading. The durable PVC is a great option for your boat trailer and will be a noticeable upgrade over the standard black rubber style you typically see in other boat trailer rollers. The Poly Vinyl construction will not mark up your boat or dry rot in the sun. This setup is suitable for either freshwater or saltwater marine use, and you can easily mount these skid pads using Stainless Steel 12 x 1 Hex HD Screwsto secure them to your trailer's crossmember.