ITEM NAME:Drill Stop Bit Collar Set with Allen Wrench 3mm Description: Internal Diameter: 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 16mm Drill Bit Stop Collar is mainly used for fixed limit drilling depth on the drill bit Bit Limit Rings are used as a Shaft Collar on machinery and can be used on twist drill bits or brad point drills or any type of bit to prevent excessive drill bit penetration The durable alloy steel setscrew type collar will not damage bits This drill stop includes allen wrench for tightening stops set screws Material: Carbon Steel Package Includes: 2 x Drill Bit Depth Stop Collar 2 x Hex Wrench SKU: DMO0013045860024019.Bit Limit Rings are used as a Shaft Collar on machinery and can be used on twist drill bits or brad point drills or any type of bit to prevent excessive drill bit penetration. Drill Bit Stop Collar is mainly used for fixed limit drilling depth on the drill bit.