The Attwood Bow Roller 11230-1 is for use on boat trailers with automatic adjusting roller systems. Its surface is smooth for easier rolling. It is made from natural rubber. It has a pre-drilled hole and has a steel insert for easy and correct mounting. Use several rollers along the keel of the boat to make loading and launching easier. Check rollers after launching to make sure they roll easily and are not damaged and in need of replacing. Attwood Corporation has been an award-winning leader in engineering, testing, and manufacturing the highest quality marine products for over 100 years. We deliver safe and reliable lighting, fuel systems, water systems, seating & pedestals, swim ladders, custom upholstery, and general marine accessories that are easy to install and meet regulatory compliance.