I keep all my batteries in a Battery Buddy Case available at many retailers. There are no dedicated slots for AAAA batteries (often used in Tablet stylus) If you stick it in one of the AA slots or AAA slots it slides too deep. Created a short sleeve to insert into AA slot to hold battery. can also be used in AA storage slots on back side. just created in Bambu slicer with a primitive cylinder and another cylinder for negative space.