While researching NorcrossFlyer's HDM Z1 mentioned in the thread "CPAP First Time Camping" I stumbled across this Heat/Moisture Exchanger, http://www.cpap.com/productpage/hea...oyzVhiEGcFOIw5D-m30dX6cp31icMlc_WZBoCYfHw_wcB It fits between the mask and standard hose and returns moisture and heat from the exhale in the next inhale. They say each unit will last approximately one week. Obviously if your mask vents exhale directly to the air, like my old style mask did, it will not work, but with my current Airfit P10 it might. This could be a boon to cpap users camping in arid areas or cooler climes. I am going to order 6 of these for our next extended trip and will try to remember to report back with results. But that won't be for a few months so if anyone has used these before I'd appreciate your feedback.