A B Brake Type: Total Lock , Caster Load Rating Range: 300 to 999 lb. , Frame Finish: Zinc Plated , Frame Material: Steel , Hub Material: Steel , Inside Bolt Hole Spacing: 5-1/2 x 5-1/2" , Load Rating: 550 lb. , Mounting Bolt Dia.: 5/8" , Mounting Type: Plate , Outside Bolt Hole Spacing: 5-1/2 x 5-1/2" , Overall Height: 12.125" , Plate Size: 6-7/8 x 6-7/8" , Plate Thickness: 0.157" , Plate Type: D , Ply: 4 , Raceway: Double Ball , Wheel Bearings: Roller , Wheel Diameter: 10.25" , Wheel Width: 3.375"