This boat trailer upright guide on kit comes with two Upright Galvanized guides, manufactured out of 1 1/2 inch square hot dipped galvanized steel tubing. The upright guides measure 48" inches tall with the legs measuring 24" inches long. The length of the leg allows for easy adjustments to fit your boat properly. This Kit also includes two PVC Sch. 40 poles and caps. The upright guides are designed to have the 2 PVC pole slide over top of it. The guides will typically attach into a cross member or by using u-bolts to attach to an I-beam frame. Will also commonly mount on square tubing frames with 1 1/2 inch Galvanized Boat Trailer Hat Bracket and by choosing the correct size of U-Bolts. For I-Beam Frames in most cases using (2) U-Bolts per side is adequate without using the 1 1/2 inch Hat Brackets.