METRIC DIN N/A ISO N/A BS N/A
THERE ARE MANY DIFFERENT TYPES OF ALL METAL LOCKING NUTS, ALL SLIGHTLY DIFFERENT IN LOOKS TO EACH OTHER, HOWEVER THEY ALL DO THE SAME JOB.
GRADE 4 STEEL ZINC PLATED.
GRADE 8 STEEL ZINC PLATED.
GRADE A2 = 304 STAINLESS STEEL.
GRADE A4 = 316 STAINLESS STEEL.
DIFFERENT TYPES - PHILIDAS, STOVER, BINX, AEROTIGHT.