The GCE Healthcare Zen-O Lite Portable Oxygen Concentrator is a compact device designed to give patients who require long term oxygen therapy the freedom to live an unrestricted, convenient life. It is lightweight (5.5 lbs, without carry bag) and built to be highly durable, to be easily carried where ever you need to go! One of the amazing features is advanced technology that delivers oxygen on demand by automatically responding to the patient’s breath rate. This feature is triggered when the patient's breathing is increased during physical activity, such as climbing stairs or walking up hill.