These will hold your tool out of the way why your are using your flex shaft. Adjusts from 11 inches to 22 inches in height. This holder is made so that the handpiece will hang down below the edge of the table when not in use, allowing enough leash to work with the tool. Adjustment is through a simple twist lock system, so you can adjust the height to any height between 11 and 22 inches. Will clamp to a workbench up to 2 1/4 inch thick.