Is there somewhere where I can find more info on these?
When were they made?
unless mistaken, this was the original website:
http://www.bit-card.de/ (I know the card has bit-card.com but when searching I found the .de one which was also dead)
I see it says "wallet-card" on it as well so this could be them as well - at least as they are now. the cards look different, concept appears the same though.
https://www.cardwallet.com/en/shop/but I could be wrong. It's just what I found when trying to look them up.