ActionHeat 3.7V 2200mAh Rechargeable Battery Kit for Socks Rechargeable Lithium Ion (Li-ion) 18650 Backup Power Batteries in the Device Replacement Batteries department at Lowes.com
Li-Ion 3.7V 2200mAh With Charger-Protection Circuit Kit Generic | SUNROBOTICS
Lithium Ion Cylindrical Battery - 3.7v 2200mAh : ID 1781 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits