What does a female coupling look like?

What does a female coupling look like, female coupling is plumbing fitting with internal threads, appearance is short cylindrical piece of metal or plastic with hollow center and threads visible inside opening, designed to receive male fitting with external threads. Female coupling typically looks like short tube or ring, often brass, copper, galvanized steel, PVC, or stainless, with hexagonal or round exterior for wrench grip, and inside has spiral grooves that are threads, usually female pipe thread FPT or female iron pipe FIP. For example, brass female coupling looks like small brass cylinder about 1 to 2 inches long, with smooth outer surface sometimes knurled or hex shaped in middle for wrench, and when you look inside, you see threaded interior. In PVC, female coupling is white plastic fitting with socket on one end and internal threads on other, or both ends internally threaded. Compared to male coupling which has threads sticking out, female coupling threads are recessed inside. Quick connect female coupling looks like socket with locking mechanism and O-ring inside that receives male plug. So female coupling appearance is short cylindrical connector with internal threads hidden inside, meant to screw onto male threaded pipe.