CE Smith 60 Post Guide-Ons with I-Beam Mounting Kit These 60 beams help you keep track of your trailer when underwater when loading your boat. Specifically designed for I-beam trailers and boat lifts. An innovative two-piece mounting clamps work above or below the I-beam. Works with almost any I-beam width and the brackets fit onto any height. Product Features Installation Instructions Included Adjusts out to 19 on each side 1-12 square, 16 gauge pre-galvanized steel uprights 2-38 Diameter white