This is a very small, extremely lightweight battery based on Lithium Ion chemistry, with the highest energy density currently in production. Each cell outputs a nominal 3.7V at 400mAh! Comes terminated with a standard 2-pin JST-PH connector with 2mm spacing between pins. These batteries require special charging; do not attempt to charge these with anything but a specialized Lithium Polymer charger. The battery includes built-in protection against over voltage, over current, and minimum voltage. Please use caution when using this battery in wearable projects. When using conductive thread, a short in the thread can create sparks and heat. We recommend using coin cell batteries. Note: This battery is not available to ship to Alaska or Hawaii, or through any express services (2-day, overnight), or internationally. This is temporary! Check out our blog post for more information. Additionally orders may take longer to process and therefore do not qualify for same-day shipping. Sorry for any inconvenience this may cause! Note: This item is non-returnable. If this item arrives damaged or is not functioning properly, please do not hesitate to contact us to see if further actions may be taken. https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2016-10-20 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2016-11-26 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2016-11-28 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2016-11-29 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2016-12-09 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2016-12-13 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2017-11-24 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2017-11-28 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2018-05-05 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2018-11-21 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2018-11-27 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2022-02-21 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2025-03-24 https://elecena.pl/product/6465970/lithium-ion-battery-400mah 2025-04-12