Built-in protection circuit (PCM) prevents over charging/discharging.
3.7V 600mAh LiPo 1S Polymer Rechargeable Battery: MP3 GPS Speaker Tab - 502060
3.7V 90mAh LiPo 1S Polymer Rechargeable Battery: MP3 GPS Speaker LED - 301228
3.7V 500mAh LiPo 1S Polymer Rechargeable Battery: MP3 GPS Speaker Watch - 602530
3.7V 500mAh LiPo 1S Polymer Rechargeable Battery: MP3 GPS Speaker - 502540
3.7V 300mAh LiPo 1S Polymer Rechargeable Battery: MP3 GPS Speaker LED - 351743
3.7V 800mAh LiPo 1S Polymer Rechargeable Battery: GPS Camera Speaker - 802535
