The E8 keychain light uses the same concept as RovyVon's hybrid battery system and the body is made of polycarbonate with a clear window, you can see the parts inside, it uses an AAA replaceable battery for extended use if it's not able to charge the built-in 330mAh Li-po battery via a USB-C device or power supply.
On the left side, there are 3 LEDs as the secondary options besides the primary LEDs.