Complete sign bolt kit 5/16-18x2" stainless steel hex head bolts, 5/16 nuts, 5/16 flat washer & 5/16 lock washers. Designed for installation via spanner, the hexagonal heads are a more favorable size and shape for heavy-duty applications. Fully threaded with industry-standard coarse threads, these bolts are suitable for situations where the fastener shaft is completely inserted into threaded hole and can secure two threaded sections. Chemical resistant, made of 18-8 stainless steel. 95TSS has everything else you need, from galvanized steel sign posts to quality .08 aluminum traffic signs.