Self centering bunk glide on's made with Tie Downn++s enhanced PVC. Launch and load made easy. Ideal for painted fiberglass or aluminum boats. Slide on or off with less effort. Easy to install. Includes 2 left and 2 right self centering glide-ons with rounded end caps to fit two 2" x 4" x 8' bunk boards. Includes stainless screws.