Lithium Ion Cylindrical Battery - 3.7v 2200mAh : ID 1781 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Olight 18650 Li-ion Button Top Battery 2600mAh 3.7V
Source High Quality 3.7v lithium ion battery 18650 1500mah 18650 li ion battery rechargeable for flashlights on m.alibaba.com
Rechargeable battery 18650 Li-Ion 2200 mAh 3.7V - Cablematic
Amazon.com: Galaxy SHENMZ 2 Pack Battery for 3.7V 3400mAh Flat Top Battery, Rechargeable, 2 Bay USB Battery Charger for Flashlight, Camera, Small Fan, Sound Equipment.… : Electronics
4pcs Batteries Led 18650 1200mah Li-ion Battery 3.7v Lithium Rechargeable Battery Blue High Capacity For Flashlight - Rechargeable Batteries - AliExpress