Not magic, just perfect! When we first tried these taps (recommended by customer Dan Baldwin), we thought they were extra hard, coated or treated somehow . . . they're that much better than any tap we've ever used before. But, the U.S. company that's been making them since 1912 says the secret is plain old care and quality control. The ground threads are held to incredibly tight tolerances for roundness, thread spacing, etc. Result is, all the teeth cut equally so the whole tapping process goes faster, the taps last longer, breakage is cut way down and the threads are the finest you'll ever see. Try them; you'll tap more holes per tap than you thought possible! Premi Mfg: Reiff & Nestor Company SPECS: H-2, High Speed tool steel.