Extreme Max Adjustable Roller 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. These guide-ons feature a full 24” of adjustable width, 90° - 70° pivot and 28” - 40” height adjustment to perfectly conform to your hull. 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 kit available for trailer frames up to 5.25" tall (Extreme Max 3005.4050). 8" bolt kit available for trailer frames up to 6.25" tall (Extreme Max 3005.4053).