Features: Made of high strength carbon steel, specially designed not to damage the bits, strong and sturdy.Fixed on the drill bit to accurately limit the depth of the hole, ensuring the accuracy of every operation in the work.Stable combination with drill by tightening the screw, giving exact drilling results.The drill stop ring is used as a collar on the machine and can be used with twist drill bits or brad point drills or any type of bit.Specification:Material: Carbon SteelInternal Diameter : 1/8 inch ,3/16 inch ,1/4 inch ,5/16 inch ,3/8 inch ,7/16 inch ,1/2 inch (3, 4, 5, 6, 8, 10, 12mm)Material: carbon steelcolour: blackPackage Contents:1 set x limited drill ring(7pcs)1 set x drill ring wrench wrench(8pcs)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.