Review (1/5): Incompatible connection
Not sure what others are commenting about the mask, etc., but this is just the short, swivel hose connection between the mask and the longer hose.
This swivel tube is too small and won't stay inside the OEM ResMed hose. So much for being universal. Plus, there's no option to return, even though it hasn't been used.
I'd appreciate being contacted by the seller.