Carbon steel material: Woodworking drill bit depth stop collars is made of high quality carbon steel, the surface is blackened, rust and corrosion resistant, high hardness, not easy to wear and tear. deform. Usage: Drilling depth stop for drill bits used to precisely control the drilling depth when drilling holes in wood to prevent wastage of material. 8 sizes: Depth stop ring consists of 8 pieces of 3mm, 4mm, 5mm, 6mm, 8, 10mm, 12m, 16mm and small wrenches. Different specifications can meet different needs. Screw fixing: Fix collar depth stop drill bit by tightening the screw. The good adhesion of the screw can prevent the stop ring from slipping and achieve precise drilling depth. Easy to use: Just put the limiting hole in the appropriate position of the drill bit, then tighten the screw to fix the limiting ring, the operation is simple and convenient. When drilling, the required depth is always unexpectedly exceeded. How to use effective force without overshooting This is our solution The drill stop kit fits most drill bits and can be easily adjusted to the exact depth required. While avoiding over/under drilling, it immediately presents holes of equal length and precision. The bit has built-in screws that can help you adjust the size and pressure used to tighten the bit without damaging the bit. The Allen wrench will help adjust and install/uninstall the plug and can also be used for any other project. Multiple size options: 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 16mm. Compatible with any wood, metal, concrete or masonry torque drill with hex set screws. In jobs where precise drilling is required, it is cushioned to prevent errors and wasted material. how to use: 1) Slide the correct size stopper to the required depth in the drill bit. 2) Align the locking screw with the floor (main body). 3) Tighten the locking screw with the wrench provided. Note: 1. Make sure the screw of the nut is firmly fixed in the center of the flat part of the bit and tightened. 2. Do not perform the exercise at high speed or he will lose his balance.