High quality materials: Drill Bit Depth Stop Made of high quality carbon steel, the surface is blackened, rust and corrosion resistant, high hardness, not easy to wear and deform. Multiple sizes: Depth Stop Drill Set consists of 8 pieces of 3mm, 4mm, 5mm, 6mm, 8, 10mm, 12m, 16mm and small wrenches. Different specifications can meet different needs. Easy to use: Simply choose the appropriate size bit and stop collar, slip the collar over the bit and set the required depth with a ruler or depth gauge (not included), then tighten the collar screw with the included bit hex key key. Improved design: The split-ring design allows the stop collar to lock securely along the diameter of your bit, Screw-in bottom collars can cause misalignment or damage to the bit, but our split-ring units Improved bits have a split design with a face parallel to the axis of the bit and they do not move or ride on the bit after being tightened. Usage: Depth stops for drill bits used to precisely control the drilling depth when drilling holes in wood to prevent wasted material. Note: The data are all manual measurement, please allow some 1 - 3cm error, due to the difference in light and display, there will be a certain color difference, depending on the physical object received Shipping Quantity: (according to the main image)