I bought 2 of these along with 2 of the new Easybeath 500 masks. I tried to search all over to make sure that this was indeed compatible with the new version of the masks and not just the old ones. Since the masks are Easybreath 500 and this accessory states that it is made for the Easybreath 500 I figured it would work. In addition, this accessory comes up on the "Our Recommended Products" section for the product page of the new Easybreath 500 - figured it had to be fine. Order arrived and it is not compatible!
I now see that there is another similar accessory which states in the name that its for the Easybreath 900 - but if you read the description, it says that it will work with the "New Easybreath 500".
Very frustrating as I have now been and returned from my trip where these would have been great.