Feature: 1)Latest bluetooth 4.1technology, offering you perfect HD stereo sound. And it's easy and fast pairing with smartphones, tablets and other Bluetooth enabled music devices. Can connect with two mobile phone at the same time. 2)In-ear earphone, Human Engineering design, very comfortable and stable 3) CVC 6.0 intelligent noise-isolation technology. Away from the noise, fully immersed in the beautiful music 4)Built-in rechargeable Li-battery, last up to 5-6 hours talking/ playing time, 1-2 hours charging time, 300 hours standby time 5)Built-in microphone for handsfree calling. 6)Volume control, answer / end phone call and play or pause music. Specifications: Model: YOLOPE A2 Bluetooth Version: CSR4.1 Operation range: Up to 10 meters Protocol: A2DP, AVRCP, HSP, HFP, SPP Frequency Response: 20Hz ~ 20kHz Double battery: 80mAH Talk Time: about 5-6 hours Charge Time: 1-2hours Charge Port: Micro USB Speaker size:9mm Weight: 15.4g