Elastic Strap closure
Somatological design provide most comfort to users . Comfortable fabric,adjustable nose pad and hanging ear design Elastic strap to meet most people's specific needs.
Two valves design act as blockers to the air, which help to achieve the effects of high altitude&low air concentration condition. This will increase the efficiency of your lung capacity training to some extent.
The face cover is Excellent in windproof and dustproof performance, typically good for buyers who like cycling, running, or doing other outdoor activities.