The LiftMaster G3712RV 12‑Foot I-Beam Rail Assembly is a one-piece rail designed for use with compatible LiftMaster and Chamberlain chain drive garage door openers, providing smooth and reliable operation for 12 ft (3.66 m) doors.

• One-piece 12 ft I-beam rail assembly suitable for residential garage doors up to 12 ft tall

• Provides stable, dependable operation with compatible LiftMaster and Chamberlain chain drive openers

• Genuine LiftMaster replacement part for reliable quality and fit

• Also known by alternate part numbers: MR3712RV, 3712PL, 012381037124, 3712RV

• Compatible with LiftMaster opener models 87802 and 8587W

• For more information visit Manufacturer's Website