This is the common replacement part for the Coats® Rim Clamps machines. The barrel also know as the sleeve of the larger bead loosener cylinder. Early models of the tire machines were made of black fiberglass. These barrels were great as they did not rust. However they were prone to failure as the fiberglass resin would chip. These chips would cause air to bypass the piston causing the cylinder to underperform. Machines now use aluminum barrels for longevity and rust prevention.
If you are thinking about replacing your sleeve we highly recommend to replace the seals as well.