There are two types MIOPS Splash.
USB Powered Version:
Your MIOPS Splash comes with Micro USB power cable so you can attach it to any USB power source to turn it on.
Battery Powered Version:
MIOPS Splash operates with a single 23A (12V Alkaline) battery. It is important that you use a compatible battery only. Otherwise, you may damage the unit. You can change the battery by removing 4 screws on the back side of the device.
In order to change the battery, turn it off first. Then remove the four Philips screws. Then you can take the bottom cover apart from the unit. You can remove the battery with a flat head screwdriver. Be careful not to damage any component on the board. Put the fresh battery in by observing the battery polarity