The recent thread about RS packing conveniences (here: https://community.ricksteves.com/travel-forum/packing/valuable-purchases-due-to-rs-or-forum-recommendations) included several positive mentions of his small lambskin wallet.
This impressed me enough to do a little digging/online shopping, and I found another wallet that has the same dimensions and same price (or even less) as the RS wallet made by Chums, the sunglasses strap people. It's made in the USA (well, Utah) of ripstop nylon and aimed at surfers and fishers, comes in many colors and patterns, and is called the Surfshorts Wallet:
https://chums.com/collections/wallets
It weighs very little, and it has a clear window on one side and a tuck-away keyring on the other.
In one zippered compartment I can just fit in US notes folded in half; have not tried Euros or other currencies yet.
In the other zippered compartment I can fit an ID card plus three other cards -- perhaps a room keycard, a credit card, and an ATM card? There is a divider so the iD can stay put in the window as you take the other cards in or out.
Whereas the RS lambskin wallet contains a joke card for pickpockets, the Surfshorts wallet has a joke Utah driver license. Chums seems to claim that this card can be used as an RFID blocker if left inside, but it doesn't seem to be anything more than a card to my eye.
I will give a review once i have used it for a while.
Question for the lambskin wallet fans: Where do you carry it? Pants pocket? Jacket pocket? Cheek pocket? (last question for squirrels only)