The EverFlo Q stationary oxygen concentrator is the newest addition to the Freedom Series line of oxygen therapy products. It provides ultra-quietâ€”40 decibelsâ€”oxygen therapy. The five-liter EverQ weighs 31 pounds and is available with or without an oxygen purity indicator. It is low maintenance, with only two filters to maintain and no provider filter change for two years. It uses less power and produces less heat and does not require patients to replace a filter.