Patent protected technology provides high quality audio even under windy outdoor conditions and traffic noise. The Cardo Scala 500 works with all Bluetooth phones, offering Headset and Handsfree profile compatibility, up to a range of 10m. The Scala 500 offers both functionality and comfort - you can chose between an ear loop and a eye/sun-glass loop, and can expect around 9 hours of talktime (with a week on standby!) Other functions includes voice activations (on supported phones), redial and call reject, all selected using the large, easily accessible control button. Unit comes supplied with USA 110V Power Supply.