All Kennedy screwdriver bits have a hardness of 58 - 62HRC. High alloy chrome molybdenum steel for use on hand and power tools. Flat & Crosspoint Bit Set Flat: 3, 4, 5, 6 and 8mm. Crosspoint: No.0, 1, 2 and 3. All 1/4”?hex. x 25mm overall length, complete with quick release 1/4” hexagon bit adaptor.