3.7V 100mAh LiPo 1S Polymer Rechargeable Battery: MP3, Video, Reader Pen - 500839
Built-in protection circuit (PCM) prevents over charging/discharging.
Actual measured dimensions (mm): D4.8 x W7.6 x L38.8
Shipped fast and secure from the UK (global shipping available).
If you have any questions at all, or if you don't see the battery you require, please ask.