1/2" inch (12.7mm) Flanged Ball Bearing with 1/4" inch (6.35mm) diameter integrated 7/8" inch (22.23mm) Long Axle, Pin Diameter is 1/4" inch, Bearing Outer diameter is 1/2" Inch (12.7mm), and Width of the assembly is 7/8" Inch (22.23mm Long), Bearing is made of Chrome Steel.