Made of quality soft neoprene that is made to flex, twist and bend but not stretch out of shape. Stands up to the toughest of workouts and marathons. It's ultra lightweight for speed and comfort. Offers full screen coverage yet you will retain full touch screen functionality. The armband includes a reflective strip for safe running in low light conditions and a secure built-in hidden key holder.Full headphone jack support for most phones. The screen suits for mobiles no bigger than 4.7''. The band fits arm size up to 16".