Features & details 【YOU WILL LIKE IT】: We use the food-grade silicone gelHarmless to human body,Can be worn at ease,And our product ha passed SGS international certification.Also passed european RoHS certification,It is harmless to human and environmental protection,This is our latest model based on 3 generations of workout mask.TIPS:The new product is sealed,Please used after ventilation.Buy a suitable size for yourself;) 【BENEFITS】: Breathing is always the key;Altitude sport masks can help increase your lung capacity and make your exercise more effective by simulating high altitude exercise,The workout mask can cut your exercise time in half.It is very important to choose an elevation mask that suits you.Take your fitness, sport and game to the next level by adding the cardio mask into your workout routine. 【SIX LEVELS OF RESISTANCE】: Change your breathing intensity during exercise,This gym mask comes with a 6-level valve system, from light to extreme, depending on your endurance.FDBRO sport masks have already met customer needs very well.The high-quality Lycra fabric and food-grade silicone gelHarmless,It is very suitable for any sport - cardio, including gym, cycling, running, high altitude training and elevation training,etc. breathing training and you can exercise breathing anywhere. 【DURABLE & RELIABLE】: Exercise mask is made from high quality ultra durable construction. Made with sturdy elastic straps.The sport mask made of Lycra material and food-grade silicone gelHarmless is more delicate and more skin-tight is a perfect combination.There will be no abnormal noise, no looseness.Three sizes for you to choose,Small,Medim and Large,By comparison, you will understand which workout masks is more suitable for you;)