Lithium Ion Polymer Battery - 3.7V 70mAh | TinyCircuits.com
Lithium Ion Battery Pack - 3.7V 6600mAh : ID 353 : $24.50 : Adafruit Industries, Unique & fun DIY electronics and kits
LCD 5V Dual USB 3.7V Lithium Li-ion 18650 Battery Charger Module DIY Power Bank | eBay
Amazon.com: HXJNLDC DC 3.7V 5000mAh 755590 li-ion Lithium Ion Polymer Battery Replacement for DIY 3.7-5V Electronic Product, Mobile Energy Storage Power Supply : Electronics