Manufactured from select quality carbon steelIndividual Punches are through induction hardened, which imparts durability and extended life for repeated useHardness at Stamping end: 5862 HRCHardness at Striking end: 3842 HRC. This prevents splintering of the punchChamfered striking end prevents breakage and accidents due to flying splintersNumber Punch Set contains 9 pieces 0 to 9. Numbers 6 & 9 are interchangeableLetter Punch Set contains 27 pieces, alphabets A through Z and ampersand &