Description Adjustable collars make drilling fast, easy and accurate. Slip the collar onto the drill bit and tighten the locking set screw to allow you to drill holes to exact depth without guesswork. Can be used on brad-point or twist drills. Grub screws can be set on the bit web or shank. – Includes 1/8″, 3/16″, 1/4″, 5/16″, 3/8″, 7/16″, 1/2″ (Drill Bits not included) – Adjustable collars make drilling fast, easy and accurate – Slip the collar onto the drill bit and tighten the set screw to allow you to drill holes to exact depth without guess work – These stop collars are precision machined and balanced from solid bar stock – Reamed bore is closed-tolerance controlled