Tie Down self centering modular bunk glide-ons feature interlocking modular sections. Tie Down modular glide-ons are designed to fit various bunk board lengths. Ideal for painted, fiberglass or aluminum boats. Kit includes four 3-foot sections and four 1-foot end sections and mounting hardware including 3/4 inch stainless steel self tapping screws. Slide on or off with less effort.