Specifications Model: BM2 Color: Black,Blue,Rose Gold,Gold,Silvery Material: Aluminum Alloy + Plastic Rated Power: 2W Transmitting Frequency: 20Hz - 20kHz S/N: > 80dB Speaker Parameter: 30.5mm Battery Type: Lithium Polymer Battery Battery Capacity: 3.7V / 300mAh Charging Voltage / Current: DC 5V / 300 mA Transmission Range: Approx. 33ft /10m Music Playing Time: Approx. 2 - 4 hrs Item Size: Approx. 30.5*25 mm