Fiberglass and aluminum boats, PWC and pontoons easily glide on and off Surfix Trailer Glides. * Solid High Density Polyethene ½" thick glides provide full bunk support; no more uneven spaced pads to leave marks on the hull. No thin skin to break down and expose a cost saving Injection molded honey comb or understructure to grind against the hull. * Low profile stainless steel wide pan head screws embrace the flat deep mounting pockets. No counter sunk screws to spread the plastic and work them loose or through the material. * Quarter-rounded top perimeter and square base provides snug butting and a no-snag transition between glides. Start the glides at the rear most edge of the bunk the quarter-rounded top will be the first contact to slide on the hull; no need for a different ending cap. * The bright white color allows you to easily see and wash off any sand or road dirt that can scratch your hull.