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
10pcs ULTRAFIRE 18650 3.7V 2400mAh Batteries Blue - Laserpointerpro
Ultrafire Blue XSL 18650 3000mAh 3.7v Rechargeable Battery, 2-Pack
100% New Ultrafire 18650 Li-ion Battery 9800mAh Large Capacity Battery 3.7 V Lithium Rechargeable Battery for Flashlight and Battery Charger 2-8Pcs | Wish