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 51 inches tall with the legs measuring 25 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 and rest on the guide for the correct placement. These are the heaviest duty 1 1/2" Square Galvanized guides available. The Overall Height of the Guide Pole Kit once PVC is installed will be roughly 52 inches. The Guide Poles in this kit are bent at 90 degrees for perfect alignment with the side of your boat. This I Beam Guide Pole kit is designed specifically to mount to a boat trailers I Beam trailer frame. The (4) Galvanized U Bolts included in this kit are 3/8" in diameter, measure 1 9/16" wide, and are 2 1/2" Long. The size and diameter of this U Bolt makes it perfect to fit around the 1 1/2" Square tubing of the Galvanized guide poles, and up through your aluminum I Beam Frame. For easy installation, you simply drill 3/8" holes into your aluminum frame that match the width of your U Bolts. You will use (2) U Bolts per side.