Teac HA-P50-B Portable Headphone Amplifier, Black 24bit/96kHz High-resolution Playback from iOS Devices / PC (Windows/Mac) Player for iOS is available at Free of Charge from App Store Player is available at Free of Charge from TEAC Website Optical Digital Audio Player for Digital Audio Devices Internal rechargeable 2100mAh Li-ion battery with continuous battery life of approximately 8 hours