Mirror Sound Box FEATURES - Built-in rechargeable lithium ion battery - Chargeable via USB - High fidelity speaker for clear pure sounds - Loud volume & mini speaker - Portable, can be extended for Bass speaker Overall Specifications: Net weight: 60g Size: 60mm x 30mm ( Dia x H ) Speaker: Magnetism Prevent 40mm / (4Ω) / 2W Loudspeaker Output 2.4W Rating Power: 1.8W Frequency Response: 100Hz to 20KHz Signal-to-Noise: ≥ 89dB Distortion: ≤ 0.5% Playback Time: 4 to 6 hours Battery Specifications Battery Voltage: 3.7V Battery Capacity: 300MAH Battery Charging Voltage: 4.2V± 0.05V Charge Time: DC(± 2.5 hours) USB (± 4 hours) Discharge Time: MP3 volume in 31mv (± 2hours) MP3 volume in 20 mv (± 8 hours)