I guess they never seen a Atpac from the 1960s
Ahh memories...
I took my ow classes using using the atpac...
dive a jacket style bcd currently...
with an airsource AAS ( I know, I'm going to die )
I also dove w/ horsecollar bcd and no AAS and no computer for many many dives
still remember the classes with Atpac fondly...