Optimal size for a 12mm screw, but hard to find locally. Drilled new holes in the spindles to accommodate a larger brake with other factory parts. Took 4 holes through 2" of metal, still looks sharp but probably won't need it anymore.
Pros
Black oxide coating cools and lubricates drill bit for longer tool life.
Upon opening the box I found that there was only one drill, the title and description of the ad clearly states that it is sold in a pack of six drills. I was dying to get the job done, so I used my only practice to get the job done, which only added to more frustration. My old worn out bits did a much better job drilling holes than this brand new bit. hardly left any traces in the steel. I don't usually write many reviews, but I felt this was done to help others avoid this situation.