High Speed Steel 82 Degree Countersink and Reamer/ Step Drill Bit Style Countersink and Deburring Tool Set-5 Flutes-5 Pieces Suitable for such soft work pieces as aluminum, stainless steel and PV board; With 5 blades Specifications: 1/4'', 3/8'', 1/2'', 5/8'', 3/4'' 5 flutes and 82 degree point angle, sharp enough for cutting wood, plastic, soft metal as aluminum 1/4" Tri-Flat Shank Extremely Sharp of the blades, different sizes of cutter for demands, more precisely work done