This is a Hot-Dipped Galvanized Boat Trailer Fender Mounting Bracket that is commonly used also as a step and to mount trailer lights. Check the images attached and the measurements to ensure that this is the right fender bracket for your single axle boat trailer. This Fender bracket has varying holes diameters and spacing, which are shown on the images, so select hardware carefully, measure the Boat Trailer U-Bolts and Trailer Bolts to ensure a successful install. Also, keep in mind these are normally replaced in pairs while replacing your Single Axle Trailer Fenders. The holes you see on the top surface of the fender bracket are the ones you would use to mount this bracket to the frame. Therefore, the side with the two holes on top faces the trailer frame, with the other end, (where you see the two slotted 3/8 inch holes) mounting the trailer fenders.