High performance button head cap screws 316, sometimes referred to as \”socket head cap screws,\” \”Allen bolts,\” or simply \”button head bolts,\” are made of 316 strong marine grade stainless steel in accordance with European standard ISO 7380 for superior corrosion resistance. It can be used to fix steel to steel or timber to steel in construction with a matching hex nut, or it can be used for high strength bolting into threaded components and assemblies in engineering and manufacturing. Please refer to the chart below for the head measurements of all of our button head bolts.