8pc limit ring drill bit limit ring 3-16mm woodworking drill twist drill tile drill bit clamp positioning ring Material Depth stop pins made of carbon steel, strong and durable. The depth stop is mainly used to fix the limit drilling depth on the drill bit and accurately control the drilling depth. Hold them securely where they are placed, and the set screw-style collars won't damage the drill. Control Depth is great for drilling depth when you need to accurately measure hole depth; designed to hold your drill securely in place and grab the full diameter of the drill without the screw touching the shaft. Note: Manual measurement, there may be 1-2cm/1-3g error, which is not a quality problem. Due to different screen displays, there may be a color difference between the real object and the picture. Delivery quantity: 1 set