1/2" Inch Ball Bearing with 3/16" diameter integrated 3/16" Inch (4.76mm) Pin Diameter 3/16" x 1/2" x 3/8" Inch 1/2" inch (12.70mm) Ball Bearing with 3/16" inch (4.76mm) diameter integrated 3/8" inch (9.53mm) Long Axle, Pin Diameter is 3/16" inch, Bearing Outer diameter is 1/2" Inch (12.70mm), and Width of the assembly is 3/8" Inch (9.53mm Long), Bearing is made of Chrome Steel.