High-quality material The drill guide ring is made of high-quality carbon steel, which is durable, reusable and has good fixing effect. Package includes 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 16mm. Depth stop collars (8 pieces in total) and 1 hex wrench. High quality designThe drilling depth limiter has stronger clamping force, can lock the drill bit more firmly, is not easy to slip, is not easy to deflect, and is more stable when used. Easy to useYou need to choose the right drill bit size and ring stop, slide the drill ring onto the drill, then set the desired depth with a ruler or depth gauge. Then tighten the collar screw on the drill. Scope of applicationThe drilling depth stop kit is ideal for production and repetitive drilling work, suitable for drilling wood or walls. Note: The data is all measured manually, please allow 1-3cm error due to differences in light and display, there may be color differences, please refer to the 'actual item received.