Our Patent product! Fill water by user! -Works with all audio sources with a 3.5mm jack -Rechargeable Lithium battery inside,USB charging -Suitable for Mobile phone/tablet PC/mp3 player/Computer -Low-power Digital power amplifier module, output power:3.0W; -Hi-fi stereo speaker (4Ω/3W) -Input sensitivity ①AUX 450mV ②FM 380mV ③TF/USB 450mV -SNR≥68Db -Charging Voltage: DC 5V -Working Voltage: DC 3.7V -Battery capacity: 1000mAH