This forum often makes reference to US Divers regulators, (particularly Mistrals, Aqua-Masters and Jet-Airs) with the designations 'DW', 'DY','DX' and'DA'?). Starting on page 170, Fred Robert's 1963 printing of "Basic Scuba" contains a nice history and explanation of those regulators, but does not explain what DW, DY, DX and DA mean. Are they acronyms, or merely model designations?
Thanks, Andy