3.7V 250mAh 402030 Rechargeable Lithium Polymer Replacement Battery for DIY 3.7-5V Electronic Product, Bluetooth Headset, Watch 2-Pack

Great for “Dead Rail” power on my model railroad.

Delivery was late. New rechargeable batteries will not charge up. Use on a drone.

I bought this for The Wand Company's Star Trek Communicator whose battery had completely died. No soldering required because the connector is already attached. It's not the same physical size as the original TWC's comm battery, but it is the same voltage and amperage. My communicator charges and operates correctly again!

great product just as described .

I've been stripping the wires on these to attach them to a charging shield for electronics projects, no problems with them at all. If you're stripping them or plugging them into a breadboard or smth be careful not to cross the wires because if it's not connected to anything to protect it it'll overheat (that's not anything unique to this product, just a lithium battery thing).

well made but to big for my space

These battery are just plane bad Do not replace a real battery

not much to say their batteries and they seem to work fine I did use it in a different application where I had to cut the connector off and wire it in, but so far it fit perfect and runs fine.