The 2 PVC tubes also make it easy to note your trailers position when backing down the ramp. Designed to fit frames up to 3 W x 4-1/4 H. Guide-ons adjust out 13 on each side. Stand 40 above the trailer frame. 2-3/8 O.D. Mounting hardware included. Features: Guide-ons let you see your trailer underwaterEasily note your trailer's position when backingDesign will adjust 13'' out on each sideMounting hardware included | Smith 40" Post Guide-Ons Pair