The Quad Lock Sports Armband is the easiest and most secure way to take your phone on your next run, walk or gym session. No more squeezing your phone into an annoying plastic pouch. The simple twist and lock system makes it easy to attach / detach your phone from the running armband. The armband is fully adjustable to fit arm sizes between a circumference 17-38cm to 6. 5"-15". The patented dual-stage lock means that your phone will stay secure, no matter how fast you move those arms. Made from stretchy Nylon Lycra, the Quad Lock Sports Armband fits comfortably and securely onto your arm or over activewear. The dual-stage lock means that your phone securely sits slightly raised from the armband, so there is no friction between your arm and the phone. At just 4. 5mm thick, the Quad Lock Universal Adaptor fits seamlessly onto the back of most smartphones and cases.