21mm OD Sliding Hanging Door Rail 4 Wheels Roller Hardware – VXB Ball Bearings
National Hardware 120-in Galvanized Outdoor Box Rail in the Barn Door Hardware department at Lowes.com
Clopay Garage Door Rear Track Hanger Kit 4125478 - The Home Depot
Source sliding door trolley channel hanger roller track, hanger door rail on m.alibaba.com
Amazon.com: Sliding Barn Door Sliding Door Track Adjustable Floor Guide Wall Hanging Rail Anti-rust Save Space Spring Door Stop Reduce Noise Glass Door ,13 Sizes ( Color : Black , Size :