7pc Bi Torsion Diamond Coated Bit-Check Set. Bi Torsion Diamond bits (BDC) significantly extend service life andprevent cam-out: Microscopic diamond particles literally bite into screwheads preventing slips. The two unique Torsion zones one in the bit & one in the holder work together to absorb peak loads placed on the bit extending bit service life. Diamond bits are also hardened to a higher degree than standard bits extending life further. Unique Rapidaptor bit holder locking system for quick & easy one-hand bit change. Standard 1/4 hexagon drive. With Bi Torsion Rapidaptor holder for ultimate service life 1/4IN Hexagon drive 25 mm. bits. Pozi set contains: 2x PZ1 3x PZ2 1x PZ3.