>I've always wondered.  What does NOS stand for?

New Old Stock. Like, VW doesn't make those little one-way valves
for the power brake vacuum line in a '71 bus any more. But a lot of
dealers still have them on the shelves, at least until they all get
bought, which might not be for years. Those are New Old Stock-- factory
original, factory fresh, never used-- but been sitting on the shelf for
a long time, waiting.