1 1/8" Inch Flanged Ball Bearing with 1/2" diameter integrated 1/2" Inch (12.7mm) Pin Diameter 1/2" x 1 1/8" x 1" Inch 1 1/8" inch (28.58mm) Flanged Ball Bearing with 1/2" inch (12.7mm) diameter integrated 1" inch (25.4mm) Long Axle, Pin Diameter is 1/2" inch, Bearing Outer diameter is 1 1/8" Inch (28.58mm), and Width of the assembly is 1" Inch (25.4mm Long), Bearing is made of Chrome Steel.