Product Info Catalog Hardware Builders Hardware Connection & Wire Goods U Bolt, #536, Zinc, 5/16 x 2 x 4-1/2-In. U Bolt, #536, Zinc, 5/16 x 2 x 4-1/2-In. Request a Quote UPC: 38613126084 SKU: 661595 Model Number: N222-174 5/16" x 2" x 4-1/2",#536 zinc u-bolt.