I designed a NeoNail nailpolish organizer for my wife. I designed the bottom of the box to have slots so the individual Nailpolish flasks wouldnt be able to tilt. The slots themselves have a diameter of 25mm so any nailpolish with that diameter should fit. There is a 3x3 and 4x4 slot version, personally I would recommend the 4x4 ones.

The box itself is designed to be stackable.

The lid is just the bottom part of the box sliced off. :)

Dimensions:

Slotdiameter: 25mm

Hight: 80mm

Width and lenght: 116mm