SHORT LENGTH SIDE GUIDES .Guide on your boat safely in high winds or strong currents. The marine grade carpet cradles your boat protecting it from scratches and dings. Brackets are hot dip galvanized for corrosion protection, and fits frames 3" wide by 5" high in size. The 18" bunk boards mount 14" above your trailer frame and are set back 3" from the outside of the frame (bracket can be bent out for wider boats) . Sold in pairs with all hardware included. 18".