5/8"-11 X 3", Externally Threaded Fasteners, Machine Thread Fasteners, Machine Screws, US Units, Flat Countersunk Head, Hex Socket Drive, AISI 304 Stainless Steel (18-8)Aspen Fasteners stocks over 200,000 different fasteners in metric and inch for immediate delivery. Through our partners we have access to virtually every fastener type; standard or specialty items, in most materials. If you have any questions, can't find what you are looking for or require larger/smaller quantities, please contact us. We aim to be your fastener solution.