Features The drilling depth stop bit is made of stainless steel material, which is durable in use High carbon steel drills, and positively locks anywhere along the drill bit. This bit depth stop neck drilling is used for drilling limit and prevents drilling from being too deep As Drill Limited Ring Holding Device Positioner Screw type collar will not damage drill bits. Features : Drilling depth stop bit is made of stainless steel material, which is durable in use High carbon steel drill bits and positively locks anywhere along the drill bit. This drill bit depth stop neck drilling is used to limit drilling and prevent drilling from being too deep As limited drilling ring, clamping device, positioner. Screw type collar will not damage the drill bits. Specification: Size (inner diameter): 3.4,5,6,8,10 in Material: Stainless steel Weight: 48 g/1.7 oz (approx.) Package List: 6 x separation ring 2 x Hex Wrench Package List