This is a custom mini version of the Castle Freak design.

This measures approximately 17" from clasp to bottom (without a plant) and I'd guess the max size pot you can use for it is 4.5" wide by 4.5"tall.

The approximate measurements of the pots shown in the photos are:

Grey/Blue:
(diameter) 4.5"
(height) 4.5"
Round :
(diameter) 4.5"
(height) 4.5"
Square:
(diameter) 4"
(height )3.5"