Sizes in Set: 1/16 - 1/2 x 64ths, A - Z, #1 - #60. Number of Tools: 115. Manufactured to NAS 907 Type B geometry aerospace specifications with 135 degree P3 split point is self-centering for reduced thrust and easier penetration and Heavy-duty construction for drilling in tougher materials. Black oxide treatment adds lubricity and creates small pockets on the surface of the tool that act to hold coolant near the cutting edge. Manufactured from premium high-speed steel; Made in the USA.