The initials apparently stand for “Anti-Gravity”, which is whimsical enough. This is the original pattern of pen bought into service by NASA and the Soviet Space Programme. I have used it in the past, writing notes from an astronomy class on a university roof in a -30°C winter night, so I can report that it does work at that marginal extremity of temperature. It is, alas, still a ballpoint, and thus still demands more pressure to work than I could wish. This does, however, mean that I can also report that the thing still writes a quarter-century after it was bought, and last used not more recently than five years ago. Reliable, at least, if not showing the sort of willingness to make lines which makes fountain pens my own preference.
As a point of interest, note in the picture below the little button on the side of the pen about half-way along the clip. That releases the point to retract; unlike most ballpoints of this sort, the same button doesn’t fulfill extension and retraction functions. I suppose this is to help avoid vexing writing failures in space.
Production Run: c. 1966 – present.
Cost When New: Currently $50.00
Size: 13.4 cm long retracted, 13.2 cm deployed.
If you are relying on the preceding information to win a bet or impress a teacher, you should read the site’s scholarly caveat. Remember, this is the internet, and it’s full of bad information.