Increase your lung capacity and your athletic performance with the Training Mask 2.0, which mimics the effects of high-altitude training and forces you to inhale fuller, deeper breaths. This mask is constructed with an airtight silicone piece which rests against the face and a neoprene strap to hold it in place. Includes 3 base pieces with flux valve plungers, which you can use to open or close 1 side, and 6 air-resistance caps, which you can change to simulate training at different altitudes. Hand washable.