The Wall or Ceiling Mount Expand System includes 4 2920 Expand units sets rolls for a 2 1/2” Diameter tube. This Plastic Chain Driven Manual Lift System is good for supporting Seamless Paper and Light Weight Muslin Backdrops. Metal Chains are recommended for support of canvas-type backdrops. Hanging bracket is 18" long x2" wide . Aluminum Tubes are not included with the system and may be purchased separately. If backdrops are purchased at the time the system is ordered, we will mount the backdrops on the aluminum tubes for FREE!. *If rollers are added to system, the shipping will be (T) for Truck.