Regarding how to access the board

① Slide and remove the clamp card.

The clamp card is fixed with double-sided tape to prevent it from shifting, but it can be removed by sliding it slightly forcefully.

② Next, remove the screws and switch parts.

The switch parts are not fixed with screws, etc., so they can be easily removed by pulling or turning them upside down.

③Remove the screw hidden under the clamp.

Slide the clamp upward and remove the screw located below the clamp.

④ Separate the handle part and bellows part to access the board.

By removing the two screws and switch parts mentioned above, you can disassemble it as shown below.
Once again, when replacing batteries, please be careful not to change the battery polarity (plus/minus).
*USB-TypeC charging, which can be accessed by removing the pommel, is safe.