Long days on the water shouldn't be followed by an ordeal when it's time to load your boat. Trailer guide-ons do more than help you get your boat on your trailer: they prevent a multitude of loading problems. Guide-ons keep you from loading too deep, keep your trailer position true, and are especially helpful at night. They'll help you load faster and safer, especially at crowded launches and might even save your relationship (just kidding, that last part's kinda up to you). Adjustable roller guide-ons work on bunk or roller-style trailers. Designed for marine use with corrosion resistant construction and hardware. Note: The included hardware will fit trailer frames up to three inches (7.62cm) wide by 4-1/2 inches (10.16cm) high. To mount this guide-on system on trailer frames up to 5-1/2 inches (13.97cm) H, order hardware kit 3005.4062.