Chamberlain Garage Door Opener 8-ft Belt Rail Extension KitThe belt drive rail extension kit for 8 ft high garage doors is required for reliable, everyday operation of Chamberlain belt drive models in 8 ft garage door applications Featuring a quick install extension rail and replacement belt, the kit includes everything needed for quick and easy installation Includes one year warranty rail extension replacement belt Includes all necessary hardware and an instruction manual for easy setup Features Type 8 ft