The Attwood Bow Roller 11209-1 is 4 inches long with 3.5 inch diameter roller ends. It is made from natural rubber to help guide the deep V of your boat to the stop pylon and cushion it from jostling on the road. It has a pre-drilled hole for easy and correct mounting. Features Protects the bow of your boat during loading and during trailering Keeps your boat protected during launching and trailering Helps your boat from shifting side to side on the trailer Made from natural rubber to buffer and protect your boat 0.5 diameter mounting hole for easy installation Specifications Color: Black Material: Rubber Shaft Diameter: 1/2" Outside Diameter: 3 1/2" Length: 4"