Vincent F how is it idifferent from extra air source "2"?
DAVE S TheEAS2 has the RG2V which is a standard piston style 1st Stage with two LP and one HP port and the EAS3 has the RG3V which has a balanced diaphram and is enviromentally sealed plus three LP and two HP ports...a much better combo, I also got mine with the tank fill valve vs the air station connector, if you need to refill on the boat you can fill from partial tanks or full.
Sam S Balanced reg... Also cooler looking. I got both.