This one is all fabric, stitched together in a way that encourages it to stay closed. I had a Keyboard Wallet
for a while but it's so smooth it kept falling out of my pocket and I had a couple close calls with losing it permanently. This one is made from a somewhat rough fabric that is almost hard to pull out, but I no longer fear it will jump out by itself!
The trick to it is that the three layers are progressively longer (from innermost layer to outermost), but the ends are sewn together as if they matched. The extra material is eased into the binding at two small points, at one and two thirds respectively, making those particular areas highly desirous of folding. So far (a couple months) it works great.