1-7L Continuous Flow Household Oxygen Generator with Accessories - Portable Oxygen Machine for Home Use, Travel & Emergency Oxygen Therapy

This unit has the outer filter cover over the foam air filter which makes it last much longer even in a dusty environment. Soapy water cleans the two stage filter. I use the sprayer on the sink faucet in reverse with Dawn soap and same for the small foam filter.The control panel on this air concentrator is clear. You have flow right there and some options. Press lockout while adding water. Don't add too much or it will blow water out the tube. Check the mark for real.