Upon coming across the term ‘oxygen concentrators‘, my first guess was perhaps some sort of oxygen delivery system for students anxious to have their brains working as well as possible, prior to an exam or assessment - a bit like those athletes who inhale oxygen from an aerosol can. As it turns out, I’m not a million miles away, as the device is indeed intended for health/medical purposes, rather than some sort of industrial cleaning machinery People with respiratory problems need to ensure that their bodies are receiving enough oxygen to stay healthy - these devices ensure that you get enough oxygen to be as well as other factors permit.