It is an essential tool for precise drilling and pay for itself by preventing errors and material waste. collars can be set at any point on the drill bit shaft, and it is easy and quick to adjust. It provides exact drilling results by preventing under- or over- drilling. Features - ColorBlack - Material: Steel . - Size: Approx. 2 * 2 * 0.8cm/0.79 * 0.79 * 0.31inch(L * W * H). - It is an essential tool for precise drilling and pay for itself by preventing errors and material waste. - collars can be set at any point on the drill bit shaft, and it is easy and quick to adjust. - It provides exact drilling results by preventing under- or over- drilling. - Hardened steel collars with set-screws; includes key for tightening and loosening collars. Package list: 9 * Woodworking Drill Bit Depth Stop Collars Ring Positioner Drill Wrench Safety Drilling 3-16mm