Hello I had to break the stainless steel diameter 10 mm by successive bore (5 mm, 8 mm, 10 mm); I tried with conventional HSS drills and drill bits HSS Cobalt / titanium from other manufacturers; everything burned after 2 or 3 holes, matter and drills; I bought 2 boxes Bosch to be sure to complete the work; I realized about twenty holes with the same 3 bits and no problems, the second box has not been opened, Perfect !!! Fast delivery and more