This is the perfect tool to avoid drill bit breakage. It's one thing to have safety wire and pliers and another thing entirely to drill that 1/8" hole. It allows you to perfectly align, guide and support those tiny drill bits across the corners of nuts and bolts just like they do in the racing and aerospace industries.; M12 x 1.5, M10 x 1.5, M10 x 1.25, M8 x 1.25, M8 x 1.0, M6 x 1.0 Manufacturer's lifetime warranty