Extreme Max 3005.3828 Carpeted Vertical Bunk Guide-On System Includes a pair of vertical carpet-padded boat trailer guide-ons, perfect for low-profile or fishing boats Adjust horizontally up to 6" on a 3" trailer frame or 8" on a 2" frame Zinc-coated for freshwater corrosion-resistance, not intended for use in saltwater or brackish water Easy bolt-on installation fits bunk or roller-style trailer frames up to 3" wide x 4.5" tall* * 7" bolt kits are available for trailer frames up to 5.5" tall, see Extreme Max 3005.4062