This handy fitting is what will adapt the common 1/4 NPT thread which is on many of the beer plumbing gas fittings such as regulators and gas manifolds and on the other side it has the smaller 1/4 MFL (Male FLare). 
The male flare side is also sometimes called 1/4" SAE too and will be compatible with any of the 1/4 SAE fittings that are also redily available.
This particular fitting is made from Chrome plated brass.