UNF 3/4" Socket Screw Countersunk High Tensile 10.9 DIN7991 UNF 3/4" (16 T.P.I.) x 3", Fine Pitch, High Tensile (Grade 10.9), Self Colour. Hex/ Allen Socket Countersunk Screw/ Bolts Countersunk fasteners are designed to fit flush on the connecting surface when fully tightened.
eBay