The Chad Evolution Electronic Oxygen Conserver offered by Drive Medical is a superior oxygen saturation device. The Evolution delivers a uniform oxygen pulse which can range from 14 breaths per minute to 40, supporting a wide range of needs and activity levels. The Evolution Electronic Oxygen Conserver senses a breath and delivers oxygen only in the first half of the inspiratory cycle, resulting in no wasted oxygen while delivering an effective oxygen dose. In addition, the Evolution has a 5:1 savings ratio and liter flow settings between 1 and 7 LPM providing a high level of conservation while offering versatile liter flow options. Delivers a uniform oxygen pulse at increments: 1, 2, 3, 4, 5, 6, 7 Plus CF preset at 2 LPM|Minimum 2-year battery life utilizing 2 AA batteries|Delivers a 5:1 savings ratio from 14-40 breaths per minute|Senses a breath/delivers oxygen in the first half of the inspiratory cycle|Operating pressure range: 200-3000 PSI|Weighs only 14.9 ounces with batteries|Single push button selects the equivalent LPM dosage settings|Auto shut-off feature conserves battery life|Fits easily in virtually any carry bag