SMBT-1 CS/SS Solid Machined Ball Transfer Unit 1" Main Ball Proudly made in the USA SMBT-1 CS/SS Solid Machined Ball Transfer Unit, Main Ball is 1" Inch, SMBT-1 CS/SS stud-mounted ball transfer is a heavy duty ball transfer unit, capable of supporting as many as 33 pounds (per unit). SMBT-1 CS/SS features a 1" inch ball bearing resting on 1/8 inch individual support bearings, making it ideal for most industrial transfer applications. SMBT-1 CS/SS ball transfer is also useful for a number of different applications where traditional wheel casters are used, including retail store displays.