The Sigel 90 x 58mm Leather Business Card Book is not made of leather at all. Actually, I could have spotted that if I'd read the product description carefully, but since the title said "Leather" I didn't look any further.
Aside from that, it's only marginally fit for purpose, since it doesn't close properly once you put 114 business cards in it, despite the fact that it claims to hold 120.
If you are looking for a cheap business card holder, don't get this one because it's by no means the cheapest. If you're looking for a good business card holder, don't get this one because it's poorly designed. If you were looking for leather, just don't get this one.
Unfortunately I only found out all this once I'd already stuffed mine with 114 business cards that needed a home. The work to take them all out again is more than it's worth to go through the process of getting my money back.
Not even remotely recommended.