Digital Signal Processor Allows tuning with equalization and gain, and delivers rich natural sound. Transparency mode Can be customized by choosing between three levels of transparency in the Beoplay App. Bluetooth 4.2 interface Enables simple wireless pairing with your Bluetooth-enabled device. AAC codec support. Rechargeable lithium-ion battery Lasts up to 4 hours. Portable charging case Provides additional 8 hours of playtime. Built-in microphone Enables simple hands-free chatting via a compatible device. Intuitive touch control Change/pause tracks, take calls and activate voice commands, all without taking your smartphone out of your pocket. In-ear design Fits securely and directs music into your ears for full uninterrupted audio.