4 Pcs ICR 10440 Rechargeable Lithium Ion Battery,3.7v Batteries 350mAh (0.39 * 1.73 inch, Shorter Than AAA Size)

These batteries work exceptionally well, especially since they are not a big name brand like LG or Samsung. I have been using them in a small LED flashlight, and even though they are only 350mAh, the light still last for a good bit of time. I tested all 4 batteries on my Nitecore Battery Charger/Tester, and all of them passed. When I received them, they all had at least 3.6V in them so there was no worry about them being bad form the start.From what I can tell the are not Low Voltage protected, so be aware of the usage of the batteries to prevent running them down to their Point of No Return (PNR). Once they hit the PNR, you might as well chuck them. I haven't seen a Li-Ion battery yet that would work right after going down to the PNR, even the big name brand ones (some people claim you can recover them with special chargers, but I am skeptical). If you ask about the minimum voltage for a Li-Ion battery you will get different numbers depending on who you talk to. I say that they should never be taken below 3.0V (Under Load) or 3.2V (Static). Others will say never to take them below 3.5V, but I have taken them down lower than that and 99% of the time, they charge back up like normal. The reason you don't want to past the PNR is that with Li-Ion batteries, when the voltage drops down so far it causes a chemical reaction with the electrolyte in the cells. This reaction in turn causes an increase in resistance, which will cause a build up of heat when charging. This very reason is why you heard about how dangerous Li-Ion batteries were when they first started to come out on the open market. Even today Li-Ion batteries can be dangerous if someone is using them irresponsibly, unless the cells include a integrated circuit (IC) for low voltage protection.As for these batteries, if you are competent and use them responsibly, you can't go wrong with purchasing them. If you are scared you might discharge them past the PNR or don't pay attention and take care of your electronics, than I would suggest getting some that have the IC in them.

Never had any problems with these. Long life, charge fast, and great value for the price. Will buy again

Work fine, just don't seem to last super long

I tested these as soon as they arrived on a Li-ion battery tester. All packs are working and 3 will take exactly 350mAh with one testing at 344mAh. So all good there. Bought them to replace the battery in my Miniware ES121 precision screwdriver and it seems to be functioning the way it should be. Can't say if they will degrade quickly, but I will edit this review down the line to update it. So far so good.

These are great cells. Note that they will very quickly destroy anything that cannot handle their voltage (lots of led bulbs, laser drivers, some motors), but will absolutely gigacharge whatever can handle it. Not all products have voltage rating but it was worth the risk to see some dollar store nail file spin a dremmel. My red laser diodes have fared best with the higher voltage. For tubular battery packs (think dollar store flashlights) just wire in parallel by linking the contacts on each end of the housing, then lining up all of the batteries in the same +/- orientation.

I read both good and bad reviews on these batteries. They all arrived at about 3.7v. Two took about an hour to top out at 4.2v while the other two took over five hours to reach 4.2v. The mAh capacity for each was different as well. It's a good thing the price is fine and they come with four of them.

All of these cells worked well except 1 of them which either can't provide more than 2volts or can't provide more output than a regular 1.5v aaa. Tested with my lumintop gt nano and it worked until I got to the 4th one and then it would not power the light even in moonlight mode. Suspected Voltage issue. Tested in my lumintop aaa tool light (a 1.5v light) and it would power the light on low mode only and even then the output drops dramatically from 20 lumens to .5 lumens in about 2 minutes, any other modes would turn the light off until low was re-selected. Basically use the products image as a "3 work 1 is doa" which honestly I'm not mad about because I saw that some people were having issues with 1/4 of their batteries. Just wish there was better quality control.

Bought as an alternative to AAA. To use in a rovyvon E8 Angel eyes. A++With these batteries the difference between the built in battery is negligible.I mean it's obviously going to be brighter with the built in battery. But super usable with the 10440.