Inspired by something similar I saw in Taiwan, I decided to make a carry all that could quickly and easily be worn on any belt and taken off just as easily when you arrived at your destination, freeing you from keys, phones and wallets in your pockets.
This started as a veg tanned piece of 7-8 oz leather which was soaked in water and cured over a form to create a rigid top that holds its shape from a single piece of leather.
The finished product, after dying and stitching and burnishing. A locking clasp that can easily be opened with one hand for convenience and peace of mind:
Lots of room for all the essentials: phone, keys, wallet, lip balm, etc.