Commercial Door Opener, Manual Chain Hoist, Max. Door Height (Ft.) 16, Max. Door Width (Ft.) 22, Commercial, Industrial, Residential, External Gear Drive, Standards 1 in Bore, Includes #50 Sprocket, 1-36 Tooth, 1/4 in x 1 in Key, 26 ft Hand Chain, 4 ft #50 Hand Chain, Chain Keeper Bracket