8Pcs Drill Depth Stop Collar Limite Rings, Adjustable Dowel Shaft Chuck Positioner Locator For Drill Consistent Drilling 16 Pieces of woodworking bit depth stop collar rings in 8 different sizes, meet your various needs, suitable for lots of twist bits, multi-functional bits, woodworking bits, etc. Mainly used for adjusting and fixing limit drilling depth on the drill bit, perfect for precise drilling, which is suitable for production and repeated drilling work, suitable for drilling wood or walls. How to Use Choose the appropriate size drill bit and stop collar Slide the stop collar over the bit Set the required depth with a ruler or depth gauge Tighten the screw of the stop collar Surface treatment: Blackening treatment Internal Diameter : 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 16mm Package Included: 2 x 3mm Drill Limited Ring 2 x 4mm Drill Limited Ring 2 x 5mm Drill Limited Ring 2 x 6mm Drill Limited Ring 2 x 8mm Drill Limited Ring 2 x 10mm Drill Limited Ring 2 x 12mm Drill Limited Ring 2 x 16mm Drill Limited Ring 2 x Hex Wrench Colour:black Material:carbon steel Package Contents: 1 set x 5/8 shaft Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.