Dowel Pins & Lynch Pins. Please note that due to our automated stocking and dispatch systems, we do not offer exchanges. 6mm 8mm 10mm 12mm socket button head screws 10.9 high tensile black allen bolt this listing is for socket button head screws in metric coarse thread of m6, m8, m10, and m12 in 10.9 grade high tensile steel, and they are standard iso 7380.