Built-in protection circuit (PCM) prevents over charging/discharging.
Rechargeable Battery 3.7V 90mAh LiPo 1S Buy One Get One Free
Beats SOLO 2 / SOLO 3 Rechargeable Battery - 3.7V 350mAh LiPo 1S AEC353535
3.7V 150mAh LiPo 1S Polymer Rechargeable Battery: GPS, MP3, Speaker - 751525
3.7V 1200mAh LiPo 1S Polymer Rechargeable Battery: GPS, MP3, Speaker - 103040
3.7V 250mAh LiPo 1S Polymer Rechargeable Battery: MP3 GPS Speaker - 402035
3.7V 130mAh LiPo 1S Polymer Rechargeable Battery: GPS Watch MP3 Speaker - 362022
