I am incredibly impressed with M. Duvivier's coin box. And, as someone who has been performing with coin boxes of various design ("normal," slot, Boston, block), materials (steel, aluminum, brass), and sizes (dollar, half, quarter) for over 50 years, this is by far the most ingenious application of the Okito Box concept I have ever come across. While it can indeed perform as a standard Okito or Boston box, it's best feature is the ability to "transform" into a solid block of brass without the performer having to do any sort of switch.
The video presentations by M. Duviver are very well done. The videos are in French with voice-over translation into English, and clearly explain the operation of the box. While the basic presentations are standard in many ways, the unique nature of the gaff itself opens up a myriad of new and interesting presentation possibilities.
In addition, the machine work to create the brass box and gaffs is very high quality, and well worth the investment of more than 3 times the price of a standard brass Okito box from other providers.
The best endorsement I can offer is the response I got when I did a simple demo routine for my wife, who is both my best audience and harshest critic, She has seen literally hundreds of coin box routines done by me and others. After clearly and cleanly seeing that this was a brass Okito box with 4 half dollars put into it, and commenting on the fact that she recognized the standard turnover move, she was stunned when the coins vanished and the box was suddenly solid brass. No switch out needed for this to happen!
Personally, I wish that this box was also available in a dollar size version, because I would be first in line to order one!