Tie Down Adjustable Roller Boat Guide-Ons Tie Down Adjustable Roller Guide-Ons center the boat and trailer the safe and easy way. This roller guide provides up to 16 of adjustment 8 on each side to fit the specific angle of your hull. Guide-ons includes hot dip galvanized steel components with a one-piece adjustable clamp and U-bolt. Designed to fit all channel and tube frames up to 5. Features 16 of adjustment 8 on each side Fits all channel and tube frames up to 5 Hot dipped galvanized steel c