Material：Garage opener adjustable bracket is made of steel, zinc plated finish,durable and rust-proof,which makes it servers much longer than others Garage door adjustable bracket has different holes at the top and bottom to ensure a tight connection to the garage door Adjustable Length: Garage door parts reinforcement bracket features a two-piece adjustable design that combines the two units into one extended bracket. Adjustable to 18", 21" or 24" Universal: Adjustable garage door opener bracket can be easily mounted on residential & commercial doors, and is adjustable for compatibility with most garage door openers Garage door adjustable bracket has different holes at the top and bottom to ensure a tight connection to the garage door Product Include: 2 Pack garage opener adjustable brackets with mounting hardware