These special high flow bulkhead fittings are designed for use in fuel cells, and have a tapered inlet to improve flow. Aluminum construction w/ black anodized finish. Each bulkhead fitting includes (2) PTFE washers and bulkhead nut. PTFE Washers are also available separately in pairs. These fittings can also be used for adding a breather to a valve cover, or a drain on a fabricated tank.