GCE Zen O Lite Portable Oxygen Concentrator with Standard Battery CPO Graham Field Wheelchair Cushion with Back Support The gel cushion features the Product Type PVC Knockdown The gel cushion features the comfort and contoured fit for which gel is known Ergonomic curved rails provide support without sharp edges and reclining chairs have anti slip handgrips for added safety The Zen O Lite portable oxygen concentrator isn’t just light Flow Settings Average Runtime Setting 1 5 hours Setting 2 4 hours 30 minutes Setting 3 2 hours 30 minutes Setting 4 2 hours Setting 5 1 hour 30 minutes *Runtime are based on an average breathing rate of 18 breaths per minute