The AN14 is an adapter for the G2 that extends the body so that the B65 fits inside.
The A19 is an adapter that extends the body so that another SF123A fits inside.
As you can see:
The G2R (flashlight in the centre) has the AN14 attached.
Above is the 8NX and below is the G2.
This photo shows a G2 with Z49 Clickie TailCap, and another G2 with an A19 body extender and KT2-BK TurboHead.
And on a G2-YL:
If you use an A19 to extend a G2 to fit a third SF123A, you will need the P90 or P91 Lamp Assemblies for this 9V combination. The heat produced by these lamps may damage your G2 Lens if used for prolonged constant-on.
The G2Z bezel has a Pyrex lens and can be used instead:
I personally prefer the TurboHead options for 9V combinations (G2+A19).
Al