Brand New Aftermarket 8" Keel Roller 897-07261-00 Material: Rubber Color: Black Set up your boat trailer with this Heavy Duty 8 inch Keel Roller by Caliber, these black rubber rollers are extremely common and are usually installed along the keel of boats as a means of protecting the hull, and allowing easy loading and unloading. Color: Black (as picture shows) Material: Rubber Overall Length: 19 CM Mounting Hole Diameter: 16.94 MM Overall Dimensions: 8.5 CM PACKAGE 1 x Keel Roller For Marine Boat Engine .