PSA: This is why you should avoid Ultrafire and sketchy Chinese batteries. There's no protection circuit, despite their claim, and their advertised capacity is 9 times what they're capable of. : r/flashlight
UltraFire 2600mAh 3.7V 18650 Li-ion Rechargeable Battery Without Prote
UltraFire BRC 18650 2600mAh 3.7V Protected Lithium Ion (Li-ion) Button Top Battery - Boxed
UltraFire FLB 18650 3000mAh 3.7V High-Capacity Protected Lithium Ion (Li-ion) Button Top Battery - Priced Per Cell
UltraFire 880mAh 3.6V 16340 Rechargeable Lithium Battery With Protecti
Ultrafire 100% Brand New Original 18650 Battery 2200mah 3.7v Lithium Ion Rechargeable Battery For Flashlight Toy Battery - Portable Lighting Accessories - AliExpress
Test of UltraFire BRC18650 3000mAh (Red-silver)
Ultrafire 18650 Battery Capacity Test - TheSmokinApe - YouTube