pecifications: Product model: MK-12 Bluetooth: V4.2 Built in rechargeable battery. Built-in microphone for hands-free calls. 3W Surround Sound speaker. Size: about 4.5*4.5*5.0 cm/1.77*1.77*1.97in Bluetooth range: up to 10m Signal to noise: 80dB Battery Charger Time: 1.5 hour Working time: 6 hours Battery capacity: 300mAh Support : Headset/Hands-free/A2DP/AVRCP Feature: *Compact And Powerful: Super-portable Bluetooth speaker delivers powerful sound and robust bass through an advanced 5W driver and passive subwoofer. *Extensive Connectivity: Utilizes Bluetooth 4.2 technology for seamless device linking and a 33ft connection range. *Extended Playtime: Anker battery technology supplies 6 hours of continuous playtime on a single charge; more than double that of comparable speakers. *Built-in MIC for hands-free speakerphone from Smartphones and iPhones. *300mAH Rechargeable Battery: Built-in rechargeable Li-ion battery supports up to 6 hours of playtime.