One of the quietest, well designed, reliable stationary oxygen concentrators on the market. Invacare was a pioneer in early development of home-use oxygen concentrators, and set the standard early on, for quality design, and reliability. The Perfecto 2 V, with SensO2, provides everything one would need in a home-use oxygen concentrator – Quiet operation, easy access filters, and water bottle humidifier, high oxygen purity at all flow levels, and compact design. The Perfecto 2 has is compatible with the Invacare Homefill System, which allows for endless refills of invacare oxygen cylinders, virtually eliminating the need for oxygen delivery to your home. Affordably priced, with a 3-year limited warranty, we believe this concentrator to be a ‘best buy’ within the online, and brick and mortar marketplace. Free shipping, and no sales tax.Electrical: 120VAC +/- 10% (132VAC / 108VAC)