M1.6 to M10 A2 STAINLESS COUNTERSUNK SOCKET SCREW ALLEN KEY BOLTS SCREWS DIN7991. A2 Stainless Steel Socket Countersunk Screws. Thread Size：M1.6 M2 M3 M4 M5 M6 M8 M10. A2 stainless is commonly referred to as 304 or 18/8 because it contains 18% chromium and 8% nickel.
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