The bike rack mounts easily on the ladder of any van or RV with a 1 inch tube. One of a kind pivoting arms allows easy access to use of the ladder. Securely carries 2 bikes on the padded cradles. Manufactured from heavy gauge aluminum with a satin finish. Light weight, easy to handle and fully assembled.The 501BR is meant for a 1” tube ladder, this will not fit a 1 ½” ladder.