I am freaking out....My oxygen distributor is having a hard time keeping up w/ the demand. I normally use C size cannisters but have not been able to get them for two weeks. so i went to D size and now they dont' have those. Telling me my only option is E size which are very bulky and heavy and hard to lug around. Please if anyone has information on a POC that will put out 5 ltp CF that will not break my back lugging it around i would love to hear about it. I ordered one years ago for five grand and it did not put out enough for my requirements without setting off an alarm. The company then charged me over 600 dollars restock fee as they kept telling me it would adjust to my breathing , thus putting me over the ten day trial period. I brought this up w/ the BBB and told me too bad, buyer beware. I'm at my wits end. Live in a small town on the oregon coast where it looks like they are getting more business than they can handle.