With this device you can you can monitor your Gameboy DMG’s LiPo battery or rechargeable AA batteries with RGB LEDs! It’s positioned just below the screen, the mode (AA/LiPo), LED brightness and colour are adjustable using the buttons (the colour applies to all LEDs).
Soldering is required. You need to supply your own wire. There is a known issue where the LEDs will quickly flash when the system is powered on. Consumes about 5.5mA on the lowest brightness and 15mA on the highest brightness.