Purpose and benefits: Enables exact drilling depths with consistent accuracy using open type optical shaft fixing. Compatible with standard drill bits from 1/8' to 1/2' for woodworking, metalworking, and DIY projects, making depth control reliable and repeatable. construction: Made from metal with a silver finish. Smooth surfaces and complete specifications provide reliable performance and strong wear resistance during repeated use. Easy installation system: Each positioning ring includes secure screws that increase locking force, allowing quick adjustment and firm fixation at the desired position on drill bits without slipping during operation. Complete size range: Includes 8 rings in the following sizes: 1/8', 3/16', 7/32', 1/4', 5/16', 3/8', 7/16', 1/2'. Applications and scenarios: Woodworking: drill multiple holes at the same depth for hinges, dowels, or cabinet hardware with repeatable accuracy. Metalworking: set precise stop depths for drilling sheets or brackets to ensure consistent penetration and alignment. DIY projects: create evenly deep pilot holes for shelves, brackets, or hardware mounting, improving alignment and finish. Why it stands out: Combines a durable metal build with a simple locking system and a full range of imperial sizes to cover common drilling depths, delivering dependable performance for professionals and DIY enthusiasts.