1、Keel Protection: With a smooth surface, the marine keel roller ensures resilient protection for your boat's keel, ensuring no damage or scuffs occur during loading and unloading. 2、Enhanced Efficiency: Boat keel roller simplifies the process of loading and launching your boat, and assists in centering your boat on the trailer. 3、PU Construction: Marine keel roller has long lasting PU construction, making it highly resistant to sunlight, chemicals, and fuels, which enhances its lifespan. 4、Compatibility: Designed to perfectly fit for boat trailers, boat trailer roller is easy to install, requires a few simple steps, saves you time and effort. 5、Detailed Size: Measuring at 6 inches long and 2.6 inches wide, with a center hole distance of 17mm, please check the size before placing an order.