CE Smith 75 I Beam Mount Post Trailer Guide-Ons 27635 These 75 extra tall I Beam mount Post Guide-Ons allow you to see the location of your trailer when its under water. Designed for I-beam trailers and I-beam boat lifts, these guide-ons feature an innovative two-piece mounting clamp that works above or below the I-beam. Brackets will fit onto any height and virtually any width I-beam trailer frame. 75 Extra Tall Guides are great for larger boats with high freeboard or longer boats that where tr