I haven't used this, but as you've not had any replies, I went looking for information on it.
My brief bit of Googling disclosed that it functions as a Himber Wallet and a peek device.
I don't think it's something to bother with. I have a very strong suspicion that the sites selling it are leaving out one piece of important information, although not having seen the device in action, I cannot be certain. I can, however, be 80% sure because of the description and the photo, and because of the comment on the Penguin Magic site about it taking a couple of seconds to get the information (a fact curiously omitted by other sites).
Incidentally, this comment is absurd:
This wallet is so deceptive and flat that it will even fool magicians.
I knew how it worked just by seeing a photo, and I'm sure many other magicians would too.
There are much better alternatives around. They've been discussed many times, at some length. They should show up if you search for them.