We had slightly over 150,000 pieces of these custom 18-8 stainless steel self drilling screws manufactured for our construction customer.  The drill screws measured 1/4 X 1-1/2 with an undercut flat head and a #3 drill point.  Most off-the-shelf versions are either available in 410 stainless steel or carbon steel material while our customer specifically needed 18-8 stainless steel composition.  Full certs were available with the parts.