I got this not for doing card to wallet, but as a utility that can be used for many other effects.
Essentially this is a gimmick that makes it possible to hold-out cards from the deck and put them
back in when necessary.
I use this for a 4 ace production from a borrowed deck of cards.
Just get your MacDonald gaffed ace and hold-out with the gimmick. Borrow somebody else's deck of
cards. Produce the 4 aces, do the four ace assembly using the gaffed aces, and then ditch them out
with the gimmick. This is a very strong trick.
This is a gimmick but it is virtually
impromptu. Because if you happen to have the gimmick on you every day, which you might as well just
make it part of your daily routine, then you will always have the UCCU gimmick on you. In this sense
it is essentially an impromptu tool.