This item is manufactured with for durable and use. It's designed mainly for fixing the drill bit, the depth of drill holes and make depth of the hole consistent. It's more convenient to round wood mortise of use. Features - Color: Black. - Material: Carbon steel. - Size: 5.40X1.70X0.20cm/2.12X0.67X0.08 inch. - The drilling ring is made of premium carbon steel, , durable and . - Can quickly and easily help you drill holes to exact depths and are great for production work and repeated drilling by positively locking anywhere along the bit. - Bit rings are used as a shaft collar on machinery and can be used on twists drill bits or point drills or any type of bit to prevent excessive drill bit penetration and for any jobs that uses a bit and needs precision. - The depth stop collar fits for high carbon steel drills, and positively locks anywhere along the bit. As drill ring, clamping device, positioner. - The drill depth stop can be fixed on the drill bit to the depth of the drilling hole to ensure the same drilling depth. Package list: 3 x Drill Bit Collars 1 x Wrench