AdafruitAdafruit 328 Battery, Lithium Ion Polymer, 3.7V, 2500mAh, 2" x 2.55" x 0.30" Size

I can't use this product because of different connector for my E-Reader. I try to use this battery only using size of the battery I have to replace. It did not work.My problem is that E-Reader ECTACO K-12 simply disappears from the Market and nobody can help me to find out battery. Brokenn battery does not have any number, letters etc. to help find out what the type of battery I used many years without any problem...

Added a picture that shows both the Adafruit 2000mAh and 2500mAh battery. However one is in a cardboard enclosure. It's worth the additional size if you don't have size constraints for your project.The Adafruit 2500mAh battery is what powers my 40+ hour custom bluetooth sleeping mask/headphones. It works beautifully with the Adafruit charger module.This is currently the biggest single cell flat Li-ion battery that Adafruit sells. If you need more power than this then go with big 18650 cylinder style rechargeable. Adafruit is awesome and full of quality products. For wearables it doesn't get any better than an Adafruit 2500mAh battery combined with an Adafruit charger. They are both chalk full of circuit protections so you can create a wearable with confidence.

Overpriced

Great Deal - Fast Shipping - Recommended - Five Stars *****

It’s a battery! It works, has a high capacity, and is relatively inexpensive. What else is there to say?I used this to build a portable console inside an NES cartridge. This had more than enough juice to power my Raspberry PI, 2.2” LCD, and USB controller.