The mask selection choice is just for the ResMed machines and only affects the generic vent rate that is removed prior to leak reporting. Respironics machines don't have that choice and it is not needed because Respironics machines report total leak which includes vent rate. So on your model 450 PR...

thought I read somewhere that you need to make an adjustment on your cpap machine if you change from a different style mask. Like from a nasal to full face.
I cant find any option to change on my cpap machine. Its a Remstar pro c-flex + model 450P

Thanks

Seems like so many to choose from and you could spend a lot trying to find the perfect one. I have only used the one that came with my cpap. Its a Mirage SoftGel Nasal CPAP Mask. But they sent me a medium. It seemed to work ok, but thought it seemed small for my nose. I am a large guy so a large nos...