Titanium HSS Step Drill Bits Set with 1/4-Inch and 3/8-Inch Shanks By Centh, SAE, 5-Piece with Aluminum Protective Case Titanium Step Drill Bit Set from high quality M2 steel comes with Aluminum case and Tri-flat shank High speed steel Tri-flat shank design for sure grip for improved performance Titanium nitride cobalt coating adds a hard layer for a lifetime guarantee of fast cutting speeds Two-flute design sizes 1/4,3/8,1/2,5/8,3/4. Automatically deburrs holes as you drill High Speed Steel Countersinks are milled and precision ground to 82