S9 Autoset features

this seems to be the best machine for me to buy, but I noticed it does not have mask off alert. Is this necessary?

newname wrote:this seems to be the best machine for me to buy, but I noticed it does not have mask off alert. Is this necessary?

not really. taping a piece of the mask to your skin can be used as an alert especially if you use duct tape

Lots of people who take their masks off turn their machines off, too, if that's what you're worried about. My PRS1 machine has a mask alert, but it's so quiet, I'm not sure it would wake me. They usually won't detect a "normal" leak if that's what you're worried about.

As archangle mentions, the beep is very faint. I did wake up to it the other morning. My mask short hose had come completely disengaged from the main hose. It was time to get up anyway. I check my times and it looked like it had been beeping for about 20 minutes before I woke up. Machine was off and beeping its little whisper beep....