These bits are made of high-grade S2 steel (carbon, silicon, manganese, chromium, molybdenum and vanadium) while Chrome Vanadium drive sockets provide excellent rigidity for strength and top resistance to corrosion. The bit body hardness exceeds conventional chrome vanadium steel and the bit head is carefully heat-tempered to reach "Schrauben Schonenderes" - more gentle on screw heads. Complemented with heavy-duty PE-HD Blow Mold Case, these extra shaft length Hex Bits are ideal for jobs at tiny and hard to reach inner hex fasteners.