Hypoxic / elevation training masks

The air past those valves is 20.9% oxygen, the same as the room you're standing in.

Also called Elevation Training Mask, Elevation Training Mask 2.0, ETM

Who it's forAny man doing conditioning work with a restriction mask strapped on.

The item

Three squares: proven in human trials. Two: a strong signal. One: early human data. Striped: the trials disagree.

Emergency: call 911.

I am not a doctor. This is not medical advice. This is self-education. Talk to a physician who has your history before you change anything.