... still widely used in the market now.Remark: DK screw head diameterK: height of headL: thread lengthD: outside diameterInternational ... by Japan, DIN by Germany, ISO international etc.Often used head type (HEAD):BINDING, BUTTON, BRAZIER, FLAT, OVAL, PAN, RPUND, TRUSS, ... HEX etc.Often used driver type (DRIVER):PHILLIPS, POZIDRIV, SLOTTED, TRIANGLE, SQUARE, HEX, SIX-LOBE ...