Fastenal actually has two specific sizes of "Tower Bolts" on their web site http://www.fastenal.com/web/products.ex?N=999600001&Nty=0 Does not say if they are galvanized or not. They have lots of good SS hardware and some tower/safety related products at their stores. I bought my SS U-bolts from them. YMMV Barry - W1HFN