The part b coupler is the coupler x male NPT half of a cam and groove pair. In 3/4" and polypropylene, it covers most of what a transfer line asks for.
Size: 3/4"
Type: Part B coupler
Connection: coupler x male NPT
Material: polypropylene
Cast, machined and assembled in the USA
Assembled with solid pins
Complies with Commercial Item Description A-A-59326D for quick disconnect couplings
Not rated for compressed gas service, including air and steam