Adjustable Resistance: This exercise trainer equipped with a rotating valve and adjustable resistance settings. Rotate left and right to increase ordecrease the appropriate resistance intensity. You can easily modify the device to suit your individual needs. Safe & High Quality : Our exercise deceive is made of ultra-flexible pure ABS silicone, which can provide comprehensive muscle training for different users. Easy to Clean: Exercise trainer simple design, easy to clean. Individually packaged to ensure a clean and safe mouthpiece every time you use it. Compact and Portable: The size of the portable muscle trainer is: 3.94in*2.36in*1.25in. Wherever you are, you can integrate exercises into your daily life. Resistance trainer compact design ensures ease of use and comfort. Wide range of uses: Our exercise trainer is a must-have for sports enthusiasts and is suitable for sports such as track and field, running, swimming, gymnastics, martial arts and outdoor activities.This well-built muscle trainer is perfect for improving exercise endurance.