Amana Tool 20210 Adjustable 3mm to 7mm (1/8 to 1/4) Universal Drill Depth-Stop Adjustable Universal Drill Depth-Stops. Can be clamped onto any drill* from 3mm to 10mm. An innovation and universal solution to the problem of drilling holes to an accurate depth. Special design to minimize any marks on the surface being drilled. User friendly  quick assembly and easy drill-depth adjustment. * Drills not included.