Ideal for jon boats, bass boats and personal watercraft. The guide posts are made of 1-1/2" square, 16-gauge steel tubing and galvanized for long life. Guide covers are made from high impact non-marking molded PVC. Low Rider Guide On's give you the extra advantage of high strength and great looks for your trailer. Mounts to trailer cross members 2"x 2", 2"x 3" and 2"x 4" frames. All mounting hardware included.