Kastar 4 Pcs AAAA 1.2V 400mAh Battery and USB Charger Replacement for Active Stylus Pen, Surface Pen Battery, Surface Pro 3/4 Pen, Digital Pen MS Surface Pen, Dell Digital Stylus, Bamboo Ink Pen

Compatible with the following Models / Part Numbers:

AAAA 1.2V Batteries
Active Stylus Pen
Surface Pen Battery
Surface Pro 3/4 Pen
Digital Pen MS Surface Pen
Dell Digital Stylus
Bamboo Ink Pen
Asus Stylus
Sonic Tooth Scaler
Video Game Controllers
Bluetooth Headsets
Glucose and Blood Monitors

A wide variety of household uses.
Versatile Power For Your Household Electronics.
Use them for everyday electronics such as alarm clocks, digital cameras, and universal remotes.
Emergency supplies such as flashlights and portable radios
Wireless video game controllers, remote controlled cars, and other electronic toys.

Note:
In order to extend battery life, please charge the battery first before using it for the first time and before long-term storage.
The batteries can only be used with device and charger with protective plates installed.
The capacity of the battery is 400mAh, please charge it in low output current mode to prevent over-charge and over-heat.
Battery comes with low power due to transport security, it may reach top performance after 3 cycles of full charge and discharge.
We recommend using the battery at least once a month, long term idle may shorten battery's life.
Store it in a clean, dry, cool place away from heat and metal objects.