All of our products comply with strict quality control and advanced technology makes CCJH Sliding Barn Door Hardware more reliable. Main Material:Carbon Steel. Maximum Door Weight Capacity: 330Lbs. Suitable for door thickness:1-1/4″1-3/4″, the minimum distance from the top of the door to the ceiling is 5-13/64. Single track load per door max 330lbs. Track Length> Door Opening+150mm/6. S turdy and Durable The folding door hardware kit is made of high quality carbon steel with frosted black anti-rust surface coating, which is not easy to corrode or damage and has a long service life. Easy to Install? Our sliding barn door hardware kits come with professional installation instructions, excellent customer service, and detailed installation videos to help you with all your installation questions. Quiet and Smooth Operation? The pulley part is made of super-strong silent nylon wheels, which ensures that the rollers slide smoothly and quietly on the track, making the folding door have sufficient cushioning when it is closed, protecting the door and ensuring safety. Package Includes? Bifold barn door hardware kit includes pulle For 4 Doors.