At first glance you don't notice what it is. Just the familiar mCCR with double cells, and the double handy Oxyscan/booster assembly. Even a close look the braided (rather wound) cable protection does not reveal the jewel of engineering hiding between the scrubber and a bottle. A tiny black Delrin cylinder, much smaller than a Barry Miller torch, holds the secret, a lithium-polysomething powered solenoid with its logic.
Actually not much of logic, and that for good. Setpoint is not _set_ like you program the unit to do something, it only, by design, injects oxygen coming from a 2l/min constant mass flow orifice, when the ppO2 falls below 1.0 bar, and stops if it exceeds 1.2 bar. Parallel to the solenoid ( talk about perfection..) there is the familiar KISS-Flow through the tunable needlevalve.
There is no logic giving a false sense of security. Both cells, and the controller, are totally isolated from each other in terms of pressure, and power. The cells are next to immune to moisture, and placed so that their reading is an immediate one, coupled directly to the inhale hose.

You calibrate the sensors to air, as calibrating to oxygen could be dangerous in places where the percentage of oxygen is, ah..... arbitrarily. (With my experience from these sensors I can say they perform quite linearly)
One touch at the wet sensors, and the procedure starts with some numbers, then a cell millivolts reading, calibrate, do what you have to do, go diving.
No menues, no worry.
"Setpoint" stability was excellent. Diving was usual. Easy.

Much easier and more reassuring than a diving the YBOD or the italian clutterbox.
My only wish was to have slightly increased loop volume, as I tend to breath slow and a bit deeper.

Matthias