Bluedio R2 stereo headset is a unique and revolutionary design combination. It will present every syllable of the music greatly and take you into the most authentic and a whole new Bluedio music world. It"s a wise choice for the professional users. R2 Technical Specification: 1.RevolutionaryPowerful 8 neodymium dynamic drive units by Bluedio Lab. 2.transmitted by aptX ® let you immerse yourself in your own world. 3.Bluetooth 4.0 low energy technology.Up to 1300hrs ultra-long standby time and up to 20hrs Bluetooth music playtime. 4.HI-FI rank Monitoring Headset/headphones 5.Maxim Amplifier. Bluetooth Version: V4.0 Support: aptX A2DP 、AVRCP 、HSP 、HFP RF Frequency Range: 2402 ~ 2480MHz（ISM BAND） Transmitting Power: Class2 RF Sensitivity: < -85dBm (PER 1 %) Operating Distance: Up To 10m (free space) Frequency Response:10-22kHz Talk Time: 20hrs Music Playtime: 20hrs Standby Time: up to 1300hrrs Charging Time: 3~5hrs Charging Port: Micro-USB 5PINS Body Size:7.48x7.48x2.28 inch Box Size:11.02x6.49x3.62 inch Net weight: 260g Accessories USB charging cable 1pc 1.5m 3.5mm Audio cable 1pc Pouch 1pc User Manual 1pc