This kit replaces 50 single drill bits. Gives efficient, smooth cut. Tri-flat shank design prevents shank from slippage in the chuck. Cobalt coating for smoother, cooler cut. Self-start, no need in a pilot hole. Cobalt coating reduces friction and enables cooler process. Big bit has tri-flat shank, while the small bits have hexagonal shank to prevent slippage in the chuck. The drilled holes are automatically deburred. The M2 high-speed steel ensures long life of the bits. Includes aluminium protective case. Package size (LxWxH): 15 x 10.5 x 4.2 cm. Product characteristics: This kit replaces 50 single drill bits. Gives efficient, smooth cut. Tri-flat shank design prevents shank from slippage in the chuck. Cobalt coating for smoother, cooler cut. Self-start, no need in a pilot hole. Cobalt coating reduces friction and enables cooler process. Big bit has tri-flat shank, while the small bits have hexagonal shank to prevent slippage in the chuck. The drilled holes are automatically deburred. The M2 high-speed steel ensures long life of the bits. Includes aluminium protective case. Package size (LxWxH): 15 x 10.5 x 4.2 cm. Sizes: 1: 6 steps from 4.76 to 12.7 mm. 2: 13 steps from 3.17 to 12.7 mm. 3: 9 steps from 6.35 to 19.05 mm. 4: 10 steps from 6.35 to 34.9 mm. 5: 12 steps from 4.76 to 22.22 mm. Scope of delivery: 1 1 x / 4-1-3 / 8-step drill. 3 1 x / 16-7 / 8-step drill. 1 1 x / 4-3 / 4-step drill. 1 1 x / 8-1 / 2-step drill. 3 1 x / 16-1 / 2-step drill.