If routing plumbing thru a firewall, motorplate, or most any flat panel a straight AN male flare bulkhead is the answer you are after. One side of the fitting is longer allowing the use of a bulkhead nut to secure the bulkhead fitting securly thru the plate that the racer is running the bulkhead thru. Machined from billet alum. and anodized for corrosion protection both ends are male 37 degree AN thread. Racer has there choice of blue, black or super nickel finish. Bulkhead nut is sold separate.