"I want to slim down my wallet, but it's not realistic to limit myself to just three or four cards..." Minimalists with this same problem should definitely get to know Tenuis. We'll reveal the secrets of its "twin card slots," which will revolutionize the way you store cards.
Why do traditional wallets become thicker when you put cards in them?
In a conventional wallet, cards are stored in a stacked, staggered manner, as shown in the diagram below. If you stack five cards, the thickness of five cards increases by a few millimeters, and if you stack eight cards, the thickness of eight cards increases by a few millimeters. Even if you stack cards in a staggered manner, the center will still end up being thicker. 
Tenuis' answer: "Parallel placement"
Tenuis has two card pockets arranged side by side.
- Stores 4 sheets + 4 sheets = a total of 8 sheets, but even with 8 sheets it is only as thick as 4 sheets.
- The cards do not overlap, so the thickness is distributed.
・Card thickness is 0.76mm, 8 cards are 6.08mm → 4 cards are 3.04mm 
You can achieve minimalism without decluttering
Driver's license, health insurance card, My Number card, spare card... Carry around the eight cards you just can't get rid of without worrying about thickness. Tenuis proposes "sustainable minimalism" that isn't too strict. Of course, if you're trying to declutter, you can make it even thinner depending on how you use it.