This listing is for an I Beam Guide On Mounting Bracket Kit for Boat Trailers. This kit can also be used on Boat Lifts. This is CE Smith Part # 27682A, but we have exchanged Zinc Plated mounting bolts for Stainless Steel Bolts. These brackets are designed to mount 1 1/2" Square Guide Poles to the bottom or top of a boat trailers I Beam Frame. Mounting these clamps is very simple, the curved portion of the clamp fits over the edges of the I Beam. With a 3/8" Diameter Bolt, you run the bolt through the holes in the clamp, connecting the two pieces together. Slide the Guide on into the Square opening as shown in the picture, and tighten. These brackets are ideal for users who do not desire to drill holes into their frames for mounting the brackets. They also allow for future adjustment if you desire to mount your brackets along the frame of your trailer in a different location. Included in this Listing is (4) I Beam Guide Pole Mounting Brackets to complete both sides of your trailer or Boat Lift, (2) Stainless Steel 3/8 x 1 1/2" Bolts, (2) Stainless Steel 3/8" x 2 1/4" Bolts, and (2) Stainless Steel 3/8" x 3 1/2" Bolts. You will only use one size of mounting bolt and hardware when installing your guide poles. We include all three sizes for convenience to make this kit workable on many different widths of I beam.