The Potensic Aton 2 batteries if you store them in the charger they are designed to go into a sleep mode and discharge them to 0%.  If stored outside of the charger over a period of 2 weeks they will discharge to 70% the to 50% and stay there at 50%.  If you want to store them in the charger this spacer does not allow the contacts on the batteries to touch the contacts on the charger so you can store them in the charger and not drain to Zero.