I came across this website: Vintage Double Hose and it’s fascinating what I learned about scuba vintage equipment. Actually, I still use my US Aquarius and Conshelf regulators and, believed me, I didn’t know those were considered vintage.
The site was created by Bryan in 2004 and accoriding from what I read, he was frustrated for the lack of information and availability of parts of DA Aqua-Master. But his curiosity didn’t settle, with the help of Luis Heros they debuted in 2014 the first modern double hose regulator. They named it the Argonaut Kraken. Designed with modern standards and parts.
Their site is a pandora of information with a forum and a webstore. I myself bought some parts from him.
By the way, the customer service is excellent.
I strongly suggest you that you visit his site, you’ll learn a lot about scuba equipment, may ask question and browse catalogs.
Take a look at the Argonaut Kraken: