Adurance training mask challenges yourself to have a better workout and improvement of your overall stamina.*Features:** Oxygen mask is designed with sturdy breathable elastic straps, so it's comfortable to wear during your exercise routine* 4 levels so you can make your workout more intense* Brand: Adurance* Weight: 0.72 lbs* Model: S-HATM-01* Dimensions: 6.75 x 4.00 x 5.50 Inches* One Size Fits Most.