The multi-tooth or the triple-square, aka XZN® - this set is highly versatile and is ideal for professionals as well as hobbyists when doing jobs in industries, handicrafts and workshops. The bit heads are made of high quality S2 steel (carbon, silicon, manganese, chromium, molybdenum and vanadium), which is considered as one of the best alloys for shock resisting property in tools. The bit body hardness exceeds conventional chrome vanadium steel and the bit heads are carefully heat tempered to have Schrauben Schonenderes - more gentle on screw heads. This set is perfect to extend your 3/8 drive tool range.