Secure-fitting, adjustable earhooks for stability and light weight strengthened construction to withstand perspiration and water during intense exercise Each earbud has track and volume controls, voice functionality, and Auto Play/Pause. strong, well-balanced sound with noise isolation and dynamic range Class 1 Bluetooth allows the earbuds to connect independently, increasing range and reducing dropouts. When the battery is low, a 5-minute charge with Fast Fuel provides 1.5 hours of playback.