M4 button head allen screws. M4 Button Head Screws. A2 Stainless Steel Hexagon. M4,M5,M6,M8 A2 Stainless Steel. M4, M5, M6, M8mm. Hexagon Head Fully Threaded. A2 Stainless Steel. Manufactured from A2 stainless steel for improved corrosion resistance.