The Overtonâs Roller Guide-On assists in centering the boat onto the trailer. It is ideal for retrieving your boat on shallow ramps where the trailer is not far into the water when you are alone, or have a crosswind or current pushing the boat. Uprights with rollers come fully assembled and ready for installation.•1-1/2" pre-galvanized steel uprights lean outward 15° to cradle the boat•Guide-ons are 21" tall above the frame with 9" roller & 2" roller caps at the top & bottom •Mounting hardware included for frames up to 3" W x 4-1/4"H•Mounting brackets allow up to 13" of adjustment out from each side of the frame•Sold in pairs•Durable pre-galvanized steel Durable pre-galvanized steel resists rust and corrosion Sold as a pair | Overton s Roller Guide-On (Pair)