The Make It Snappy Tools 40030 Quick-Change 5-Piece Countersink Drill Bit Set is a combination set of premium power tool accessories. It features a 1/4? Hex Power Bit Shank.Included in the set:5 x Gold Screw Countersinks: 5/64?x3/8?, 3/32?x3/8?, 7/64?x3/8?, 1/8?x3/8? & 9/64?x1/2?1 x 1/8? Hex KeySnappy Gold Screw Countersinks, Why?Precision machined in the USA with tight tolerances to ensure concentricity and a consistent counterbore.Made of alloy steel and heat-treated to HRC 52-56 to provide long cutting life and the ability to be resharpened.Drill the pilot hole and countersink or counterbore for screws in one step.Securely hold your twist drill without slippage due to the Snappy signature oversized and hardened gold set screw.Easily control the depth of your countersink by utilizing the premium rotating depth stop.