25mm Barbell Quick Collar Insert

This is a simple insert designed for 25 mm quick-release collars used with adjustable dumbbells and barbells.
It addresses the issue where collars labeled for 25 mm bars do not clamp tightly and can slide off during use.
By adding this insert, the collar fits more snugly and initial tests show improved holding performance.

The design has only undergone preliminary testing. It has not been stress-tested or validated for long-term or heavy use.
Use at your own risk and test thoroughly before regular training.