If you fail any kind of saving throw, you can shunt that failure into the cartridge.

The cartridge has 5 charges. Upon using the cartridge to pass a saving throw, a charge is expended. These charges cannot be restored.

You may use an action to expend one charge and recover spell slots. You will gain all the slots of a target spell slot level, of any kind.

You may also Expend a charge to add an additional damage die to any spell you cast.