At home we use a 50 psi compressor for everyday use; however, on the rare occasions we travel or during the weekend at the family lake cottage we use a pari vios or an Philips respironics (sp) that we got from the DME when our last Devilbiss Pulmoaide gave up the ghost. The pari is starting to slow down, is no longer under warranty, so wondering what everyone else uses for travel, portability, not $$$. None of the battery operated appear to meet the durability or psi requirements from what I've seen. Suggestions....?