These adapter fittings thread into the O-ring sealed SAEJ1926 straight threaded ports on your Racor turbine style filter and have female NPTF* sockets which accept NPT plumbing fittings - such as hose adapters.
* Racor Turbine Series fuel ports have SAE J476 National Pipe Tapered for Fuels threads (NPTF - also known as Dryseal Pipe Thread). The crests of the threads crush slightly when tighened, allowing the flanks to make contact with each other - thus sealing the joint. Even so, use of a thread sealant (not Teflon® tape) is recommended to ensure a leak-proof seal. To avoid system contamination, do not apply sealant on the first few threads.
NPTF threads are compatible with NPT fittings.