Bell-shaped drill head allows tool to be pivoted inside drill hole helping to stay on center. No pilot hole required. * Self centering drill tip; no walking or wandering. No grinding, center punching required. * Works on jagged uneven rough breaks. No grinding, Center punching required. * Tempered twice for extra hardness. Results in multiple extractions per tool. * Made from M2 HSS. Highest quality steel used and made in the USA.