Mark, I don't understand stand your comment about not having to wear a cannula - you'd rather wear a mask? And EDS doesn't allow cannulas?

Dan is correct- I was referring to the Oximizer "mustache" cannula that looks like a large flesh colored growth on your upper lip. They help conserve O2 with a properly calibrated manual flow valve and a constant flow system, but the more efficient EDS uses a normal cannula. NOTE: Do NOT use the Oximizer cannula with the EDS! It will not reliably trigger the pressure transducers in the EDS and you will not receive sufficient O2.