This vacuum relief valve assembly is made mostly all stainless steel parts except the base plate is aluminum. Stainless steel bolt, nut, washers, and spring. Will work with most tank lid mounted vacuum relief systems. 3" X 1/8" aluminum disk 3/8-16 SS bolt X 3"L 1-3/4" spring Exact parts for the build are subject to change without notice. Special order and is not in stock. Takes about two weeks to manufacture.