Hi Steve,
I use the MS5540 1 bar sansor for reading atmospheric pressure in a sample chamber where I must know the oxygen partial pressure very accurately. I also use this sensor for altitude in bird migration studies.

I use several MS5541 14 bar sensors in a gas mixer where I can mix O2, CO2 and N2 to 0.1 mB precision. I also use these in archival dataloggers which are surgically implanted in salmon, tuna, kingfish and penguins for physiological studies of aquaculture species.

Cheers
Brian