The multi-tooth or the triple-square, aka XZN® - This compact set covers 10 most useful sizes for professionals and hobbyists to work on BMW, Mercedes, VW, Audi, Porsche, and most other European vehicles. 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. The PE-HD Blow Mold Case is for easy storage while providing excellent protection for your bit sockets and giving you high work portability.