Remax RB-M33 -The aluminum alloy base is made of aluminum alloy base by CNC die-casting. Professional audio DSP digital amplifier. Magnify the sound fidelity to achieve surround sound effect. 0.5mm thickness front metal horn mesh cover. The diameter of each round hole is kept to 0.2mm precisely by metal etching process, with strong sound transmission. Compatible with all mobile devices with NFC function, fast pairing with Bluetooth SR RK 1018 Specification Color Black Battery Capacity 1200mAh Brand REMAX Model Number RB-M33 Wireless Version V5.0 Transmission Distance 10-15 Meter Impedance 4Ohm Play Time About 4 Hours Standby Time 120 Hours Packing Include 1 X Bluetooth Speaker,1 X Data Cable,1 X Audio Cable And 1 X English And Chinese Manual