This is a stand-alone unit humidifier for a CPAP machine that was literally used for two days, then my CPAP machine broke. The new one I got has a built-in humidifier, so I do not need a stand-alone unit. I bought it for just under $200, brand new, and it has only been used for two days. It is all in excellent condition, has all of the parts, manual, etc. This unit is a great deal and will work as an add-on with any brand CPAP machine that requires a humidifier be added on. Email me from here, or call me at 817-791-1565. Ask for Chris.