1.EASY DRILLING OF VARIOUS SIZES: With 8 different sizes of precision drilling tool stop rings, you can easily complete any drilling project. The rings and allen wrenches allow you to quickly and accurately adjust the depth and secure the stop ring. Package Includes; 4/7/8 PCSx Drill Depth Stop Ring 1 x Hex Wrench 2.HIGH STANDARD OF QUALITY: These depth stop ring set stop rings are forged from high standard carbon steel and are so well made that they won't break with constant use. They are the premium material for your drilling needs. 3.EXCELLENT WORKMANSHIP: Use an Allen wrench to tighten the set screw on the selfcentering drill guide stop ring for perfect depth control. Say goodbye to inconsistent drilling depths and easily repeat drilling jobs at the same height. 4.Enhanced Drilling Control: Accurate depth measurement with our SelfCentering Drill Guide Depth Stop Set stop ring makes it easy to ensure accurate drilling. Prevents burning of the material surface, minimizes errors and waste, and enables efficient drilling.