CE Smith 27671 Pontoon Bunk Board Guide-OnsPerfect for bunk style pontoon trailers, with either a box, channel, or I-beams up to 3" wide by 4-1/4" tall. Never worry about damaging your boat while getting it on the trailer again. Your pontoon will slide across the carpeted bunk boards and onto the trailer with ease. Height is set during install but is adjustable between 24" and 36" above the trailer frame. Trailer frame cross member should be mounted with 2-3" bunks.Product Features: Zinc Plated Hardware; Galvanized Steel Construction; U-Bolt Mounting Brackets; Includes two 24" carpeted bunk boards; Fits frames up to 3" wide and 4-1/4" tall;