UP FOR SALE IS AN AIRSENSE 10, USED ONLY 4 MONTHS AND NOW, I NEED AN APAP AND/OR BIPAP. I FOUND THE NOISE LEVEL WAS A LOT QUIETER THAN MY RESMED 9. THE AIRSENSE 10 IS THE QUIETEST CPAP MACHINE ON THE MARKET AT THE TIME OF PURCHASE, WITH A NOISE LEVEL OF ONLY 26 DECIBELS, MAKING IT IDEAL FOR LIGHT SLEEPERS. THE AIRSENSE 10, INCLUDING SMARTSTART, AUTORAMP, AND CLIMATE CONTROL. THE WATER TANK IN THE AIRSENSE 10 HOLDS WATER FOR 3 FULL NIGHTS (FOR ME), THE AIRSENSE11 ONLY HOLDS 2 FULL NIGHTS. THE AIRSENSE10 HAS A TOUCHSCREEN AND A SIMPLE START/STOP BUTTON. IT ALSO HAS AN AUTO-OFF FUNCTION THAT DETECTS WHEN YOU PUT ON OR TAKE OFF YOUR MASK. I PAID OVER $1100 FOR THE UNIT, SO IT IS MY LOSS BUT YOUR GAIN. ASKING $775 SHIPPING IS AVAILABLE AT COST. THANK YOU FOR LOOKING.