Heavy-Duty Apron Bracket Sliding Door Box Rail Max Weight (Lb.) 450 lb Steel Bright Zinc Finish Length (In.) 4 5/8 in Height (In.) 8 3/4 in Width (In.) 2 3/8 in Max Wheel Dia (In.) 2 1/8 in Nylon Bearings Number of Wheels 4 Steel Hardware Included For Use With Doors Weighing Up To 450 Pounds