3/8" Inch Flanged Ball Bearing with 3/16" diameter integrated 3/16" Inch (4.76mm) Pin Diameter 3/16" x 3/8" x 1/2" Inch 3/8" inch (9.53mm) Flanged Ball Bearing with 3/16" inch (4.76mm) diameter integrated 1/2" inch (9.53mm) Long Axle, Pin Diameter is 3/16" inch, Bearing Outer diameter is 3/8" Inch (9.53mm), and Width of the assembly is 1/2" Inch (12.7mm Long), Bearing is made of Chrome Steel.