1/2" Inch Ball Bearing with 1/4" diameter integrated 1/4" Inch (6.35mm) Pin Diameter 1/4" x 1/2" x 9/16" Inch 1/2" inch (12.7mm) Ball Bearing with 1/4" inch (6.35mm) diameter integrated 9/16" inch (14.29mm) Long Axle, Pin Diameter is 1/4" inch, Bearing Outer diameter is 1/2" Inch (12.7mm), and Width of the assembly is 9/16" Inch (14.29mm Long), Bearing is made of Chrome Steel.