The C.E. Smith Company Carpeted Bunk Board Guide-Ons are designed to ensure proper center loading, and are made of Southern yellow pine and tilt to hug the hull. The mounting hardware fits frames up to 3 inches W x 4.25 inches H, and can be mounted on top of the frame for added height. 1.5-inch square pregalvanized uprights. C.E. Smith Company Carpeted Bunk Board Guide-Ons Black - Trailer Parts And Accessories at Academy Sports