This stainless steel drill guide will be of great assistance when using our SR065 kit to attempt a stud repair on a 911 head where both studs have snapped. Basically a 3/16 drill guide, one end of the SR065D is opened to 8mm to center the guide over the broken stud, allowing the 3/16 drill to then naturally find the center of the broken stud. This guide helps take some of the unpredictability out of a double stud repair when even as little as 1 or 2 mm of a stud is protruding from the head.