An M6x50 galvanised hex head bolt is a metric, externally threaded fastener designed for securing materials, commonly used in construction, machinery, and outdoor projects. The "M6" denotes a 6mm nominal diameter, and "50" indicates the length of the bolt in millimeters, typically measured from under the head to the tip. Also known as Engineer Bolt. The galvanised coating is suitable for most outdoor applications and fixing timber to timber or timber to steel. Can be used in treated timbers.