High capacity 103773 lipo batteries 4000mAh 3.7v - VATS BATTERY
3.7V 4000mah 7 "tablet battery seven inches below the sun M70 486790 p 3.7 V 4000 mah mobile tablet batteries - AliExpress
Amazon.com: Batteries ICR Rechargeable Batteries High Capacity 3.7V 4000mAh Li-ion Battery, 1200 Cycles Longer Life Button Down for Solar Lantern Battery, 2 Pieces : Health & Household