cold water/sealed regs

[jasondbaker]

Yeow, strong words. Knowing most of the people on this thread I can comfortably say most of them have dove extreme cold. Here is Apeks' version of balanced:

Over-balanced Diaphragm Design
The heart of any regulator is the first stage. Most Apeks first stages utilize a unique Over-Balanced diaphragm design. In an over-balanced first stage design, the interstage pressure in the hose increases faster than traditional balanced models as a diver descends to greater depths. This increased interstage pressure compensates for the increased density of your breathing gas by allowing a larger volume of gas to flow through the system on demand. The result is superior breathing performance regardless of depth. The Over-balanced Diaphragm Design is found on Apeks Black Pearl, ATX 200, ATX100, ATX50, ATX 40, and TX40/DS4 first stages.

Pneumatically Balanced 2nd Stage

All Apeks second stages feature a Pneumatically Balanced Valve System. In most second stage designs, the inhalation effort of the diver opens a valve inside the regulator that is held closed by spring tension. In the Apeks pneumatically balanced design, the pressure on the second stage valve is "balanced" by allowing medium pressure air to pass through to the opposite side of the valve to help counteract the force of the spring. This reduces the inhalation effort required to open the second stage valve and substantially improves the overall ease of breathing in all diving conditions.