This CNC billet aluminum adapter fitting uses 3/4"-16 port male threads and is O-ring sealed. These threads are the same used on -8AN without the 37deg conical flare. The machined female threads are 1/8NPT and is commonly used to easily adapt a fuel presure sensor, fuel pressure gauge, etc. to a fuel rail. The surface is Type-II anodized with a R5 bright dipped finish to resist corrosive fuels such as ethanol, methanol, E85, etc.