Pin jaws are popular in most chuck systems and particularly useful for mini chucking systems. They can clamp small work pieces in contraction but are also useful in expansion for common projects such as salt and pepper mills and tea light holders. The internal diameter is 6 mm, making them ideal for holding the finest of work. They also feature a slight undercut at the base to ensure it is possible to fully insert the jaws into the work piece and use the base of the jaws as a register, for accurate fixing.