I heard this called a fake battery, a dummy cell, a piece of metal, etc. Whatever you want to call it, it is there to make sure your saber functions properly.
If this comes installed in your saber, do NOT remove it, do not charge it, do not put it in any charger. Most importantly, do NOT remove it and replace it with another battery, you will damage your LED and soundboard with too much voltage. These are here to protect your saber and make sure it functions properly. Keep the battery (or batteries) in your Li-Ion saber charged and your saber will perform to it's full potential. Happy sabering.
https://www.ultrasabers.com/ProductDetails.asp?ProductCode=Z-Electronics-DummyCell
