1High carbon steel features high hardness, strong strength and long durability 23mm, 4mm, 5mm, 6mm, 8mm, 10mm and 12mm drill depth stops will fit drill bits in different size 3Help to limit the depth of drilling hole as you want 4Equipped with a hex wrench for convenient use 5Easy to use, just insert the stop collar on the drill bit to to the desired depth and tighten by wrench Description: This practical woodworking tool helps to give you consistent control of drilling depths easily. The kit including 7 depth stop collars to meet various demand: 3mm, 4mm, 5mm, 6mm, 8mm, 10mm and 12mm(inner diameter). It is made of high carbon steel, with high hardness and strong strength, easy to operate. Features: High carbon steel features high hardness, strong strength and long durability. 3mm, 4mm, 5mm, 6mm, 8mm, 10mm and 12mm drill depth stops will fit drill bits in different size. Help to limit the depth of drilling hole as you want. Equipped with a hex wrench for convenient use. Easy to use, just insert the stop collar on the drill bit to to the desired depth and tighten by wrench. Specifications: Condition: 100% Brand New Material: High Carbon Steel Color: Black Inner Diameter: 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm Outer Diameter: 9mm, 10mm, 11mm, 13mm, 16mm, 17mm, 19mm Weight: approx. 52g Package Included: 1 x 7pcs/set Depth Stop Collar 1 x Hex Wrentch