Amazon.com: ICR18500 Battery 3.7V 1400mah Li-Ion Rechargeable with Flat Top 6PC(They are not 1865mm Batteries Also Not AA Size Battery) : Health & Household
Lithium Ion Polymer Battery - 3.7v 500mAh : ID 1578 : $7.95 : Adafruit Industries, Unique & fun DIY electronics and kits
4-Pack of ICR 18650 Blue Lithium-Ion Rechargeable Batteries - 3.7V 2600mAh | xUmp.com