I know Rolly likes to tout the Sub as the OG but the FF is the true OG. Read the Navy paper on the contest amongst the contenders and the Sub wasn't even close to FF in it's capability. As I recall it would fog up rendering it useless.
My fave is probably the Rayville-Tornek version for the pure history of having to fake a US company to get the watch in the states (or there abouts)