I ordered 2 21700 batteries. Unfortunately, one turned out to be defective. It lost all its charge and when I try to charge it with an XTRAR charger, it thinks it's Ni-Mh and charges it at 1.5V. Worthless!

The best choice for a 21700 battery. It consistently provides good power even when low on charge. Ideal for medium and high Watt (40-80W). Don't pay attention to the mAh in other batteries, they don't play an important role on their own. Top Tier battery, highly recommended.

Excellent! Works well for both low and high watts (especially at high). Very good durability over time as well. One of the best 21700 batteries available, if not the best.

I don't know if the one I bought is authentic, so I am cautious in my evaluation. The nominal capacity turned out to be correct, but the behavior of the battery is strange; it discharges at an unusually low voltage below the familiar 2.7 volts. Also, the wrapping of the battery looks sloppy, and during its discharge, it gives the impression that it drops in delivered power very quickly...with so many fakes out there, go figure

For the first time, I made the switch from 18650 to 21700…. While before, as the battery drained, the performance would drop, that is not the case here!!!! I bought two and will get two more

For me, it is the best battery for both electronic and mechanical devices!! Better endurance than the Samsung 40T - 30T. I have bought 3 pairs so far.

Excellent battery for use in an electronic cigarette. I use them in a single battery mod and they still provide power even when they are discharged below 1%. Their capacity is around 4400mAh. I highly recommend them!