This is a simple battery case holder if you charge your batteries and have the same problem as me, finding batteries all over the house. I made the holder part first only to realize it is not stackable, so I decided to make a another case to serve as a lid and also make it stackable. I am an extruded plastic fan, so the "lid" was made from 3mm extruded plastic and the actual box with 3mm white MDF, I have listed them as page 1 and 2 in the files, named 1) Case and 2) Lid. You can use the AA for the AAA but be careful, the AAA tend to fall over, then you spend 30minutes trying to get it out. Unless you do not glue your top part like I did. Also take care that the holes at the bottom correspond with the top, otherwise your batteries will stand at an angle. This was good for my OCD - enjoy!