Thomas hedstrom files are unique because they have a ‘fail-safe’ screw-fit stopper mechanism that is secure, adjustable, and won't move when in use. The stopper is adjustable with a screw fixing. Each turn is 1mm, so placing the stopper exactly in the right place is quick and easy and won't move like rubber stoppers providing peace of mind when working on the root canal. - Size: #15-40. - Length: 25 mm. - Color: Assorted. **For further product information, please contact Chat Support**