YNPOWER 4 Pack Battery for 3.7V 3400mAh Flat Top Battery, Rechargeable, for Flashlight, Camera, Small Fan

Delivery was fast and batteries charged right up! Longer lasting than batteries previously purchased. I’m very happy with them!

Save your money these batteries are garbage. I got them to replace some smaller mah batteries. Unfortunately the smaller old batteries greatly outperformed these brand new ones.

Its a shame I didn't have a battery capacity checker when I bought these. I took 'em out of the box yesterday and ran them on my new Opus. The capacity is LESS THAN HALF what the manufacturer rated them to. 1.7 Ah at best. Buy if you enjoy mystery boxes.

Works wonders! Highly recommended.

The media could not be loaded.  2 of 4 of the batteries didn't work!

These are used in church wireless microphones for our vocals and they are pushed. They hold a charge throughout the service, and if push came to shrove, we could use them two Sundays without charging them. If you need a flat-top 3.7, here is your answer

I got these batteries yesterday and the first thing I did was charge them. They lasted less than an hour. I recharged them making sure they were fully charged and again lasted less than an hour. That's two sets of batteries for less than 2 hours. The only reason this gets one star is because I can't leave zero

These batteries are not great. I originally left a positive review because these look high quality but after using these for 2 months, I find they barely hold a charge.I use these in my mod. I have another set of batteries that are about 2 years old and are less mah than these but those other batteries last so much longer.I'm lucky if I get half a day with these. They tend to discharge by 10% IMMEDIATELY from a 100% charge. And once they get down to 25%, they discharge to zero after just a few minutes.I use a proper charger and store them correctly. I just think these batteries are low quality and maybe not the size they are advertised at.I gave 1 extra star for the seller because their communication has been good. I was going to reach out to them directly but I don't see a link for that.If they reach out to make this right, I will update my review again.