Extreme Max Carpeted Vertical Bunk Guide-Ons do more than help you get your boat on your trailer; they help stop a multitude of loading problems. They'll help you load faster and safer, keep you from loading too deep, keep your trailer position true and are especially helpful at night. They will fit bunk or roller-style trailers up to 3" wide x 4.25" tall*. 16" carpet padded bunks sit on 100° angled vertical arms. These guide-ons adjust horizontally up to 6" on a 3" trailer frame or 8" on a 2" frame. They can also be positioned to align evenly with the outside edge of the trailer frame. Bunk height is adjustable and the bar can be mounted on the top or bottom of the frame. Great for low-profile or fishing boats. Extreme Max Guide-Ons are zinc-coated and intended for freshwater use only. Use in saltwater or brackish water will damage the finish. 7" bolt kits are available for trailer frames up to 5.5" tall, see Extreme Max 3005.4062.