Okay, so I grabbed this 4-pack of 18650 batteries with the USB charger because my flashlight addiction demanded it. Here's the real talk:

• The charger is LOWKEY AMAZING? Individual slots with red/green lights make me feel like a scientist monitoring experiments. Plus, all those safety features mean I can charge overnight without imagining my house burning down (dramatic, but you get it).

• Batteries are... fine? Like they work, but that "5000mAh" claim is straight up fantasy. My voltmeter showed about half that. Still decent for backup power though.

• Major bonus: The USB charging means I can use my laptop, power bank, or even plug it into my car. Perfect for camping trips when I need to recharge my gear.

• PSA: The charging cable feels kinda cheap - like if I'm not careful storing it, it might snap. Wish they used USB-C instead.

Overall? Solid 7/10. Would buy again just for the charger alone, but manage your expectations on battery capacity.