Looking for A-14 (or similar) pressure breathing diluter demand regulator

I would like to correct a couple of statements made here with respect Bob Harris’s altitude record flight. My apologies for being slow to respond.
1) Bob Harris did not limit his climb “because he couldn't keep his mask on�. He terminated the climb because he believed one of his two oxygen systems had malfunctioned.
2) However, the statement that he was “forced down when his oxygen system started to fail� is also incorrect. His subsequent investigation showed that both oxygen systems were operating within specification. The problem was they were not operating identically. As Bob pointed out in his presentation to the World Gliding Championship at Benalla, Australia the following year, differences in the regulators’ pressure settings, stiction between the components, the lack of vibration in the sailplane to address that stiction and the fact that the regulators were at or near their operating limit, resulted in a substantial difference in the pressure he felt in his mask when he switched between the two systems. He interpreted this difference as an indication that one of the two had failed, but later determined it had not.
3) He did not suffer from any medical condition as a result of his record flight.
Mike Koerner