Did you ever wonder, how to completely empty your shampoo / shower gel bottle?
Some are made for standing upside down, but others are not.

Here this bottle holder comes into play: You can store the bottles upside down and use the valuable contents up to the last drop.

The thing is customizable and has two holes with different sizes.Note that there is also room for the joint between cup and lid.

From my experience it is wise to choose the hole diameter 1.5-2mm wider than the acual lid diameter.

Have fun!