ADAPTORS  ACCOMODATE PARTS WITH INCOMPATIBLE THREADS 

When you want to join two parts having incompatible threads (ie: hose thread vs. pipe thread), adaptors are used. Some fittings have only pipe threads, while others have only hose threads and some have both. While all hose threads are the same size, pipe threads can differ ever-so-slightly. To prevent leaks, use teflon tape on all pipe threads. Female Hose Thread (FHT), Female Pipe Thread (FPT), Male Hose Thread (MHT) and Male Pipe Thread (MPT) are the terms used to  indicate the thread size and configuration.