Oxygen Concentrator, Nicuvlad 1-7L/min Adjustable Portable Oxygen Machine, 30%-93% High Concentration, Oxygen Machine for Home and Travel, Oxygen Concentrator Air Purifier with Voice Broadcas

Oxygen controls easy to use. Like the variants in oxygen percentage levels. The machine is not heavy. Overall a good machine – works well, does everything I want for the price. Would recommend.