CE Smith 16870, flex keel pad 10" x 1-1/2". these black poly pads cushion the trailer cross members to protect your boat keel. Pads mount on top of frame cross members or axles to prevent direct boat keel to trailer frame contact which can be a problem when the trailer is steeply inclined on the boat ramp. Edge cover style mounts on the trailing edge of any width cross member or axle. Mount using two rivets or screws through the top (hardware not included).