This Support Arm, part number C545, is shown holding a C530 Hand-Held cap tightening unit fitted with a driver shell and insert. The C545 acts as the perfect counter-balance to reduce the stress associated with repetitive capping cycles. Some users will see a measurable difference in the repeatability of the applied torque. As a plus -- the unit stays in the position it was left following the cap tightening cycle. The C545 is 90% steel construction. An adjustable gas filled shock allows the user to tune the system to accommodate varying tool loads.