This dome lid, equipped with a non-code gasket, is specifically crafted for vacuum tanks operating under maximum vacuum and low pressure. Trusted by top OEM manufacturers of vacuum trucks, it features a 5-wingnut design, making it perfect for placement on the top of the vacuum tank. Proudly manufactured in the USA for over 45 years, this manway includes a 20" steel lid with a 6" steel neck. It comes standard with an assembled wingnut, hinge assembly, and buna gasket.