These are the singlehose regs that I found until now:

Type CA 1
Type CA 2

The first commercially successful single hose SCUBA as called the Porpoise, made by Breathing Appliances Pty Ltd, Melbourne, Australia. The inventor was Ted Eldred. His diving school was run by Commander Maurice Batterham, Royal Australian Navy. The first Porpoise was sold early in 1952. There were 12,000 made, of which 8,000 were hookah. The first model was called the CA1. The CA 2 was the two cylinder model.