If you're looking for something else than the usual MOLLE-style pouch, here's a Danish water canteen / utility carrier of relatively recent produce with the British PLCE attachment system that works better with belts.

Don't let the modern looks fool you: the camo pattern is M84 and the pouch is from the '90s. That was a time before the MOLLE system was introduced and many countries had various systems in use, most commonly copies of the US ALICE or the British PLCE systems. This pouch has a standard PLCE attachment that works with many utility and duty belts, and the back has extra loops for other strapping ideas you might come up with.

The pouch is made of stupid-strong 1000D Cordura with a rubber-like coating inside, most likely PU. The lid features a small pocket for water purification tablets and the closure has a Spanish Tab system that is secure, fast, and silent. As an additional measure of security, the lid can be closed with hook-and-loop patches on the inside. A silencer tab can be folded in between to disable this feature.

On the inside, you'll find a divider for a folding stove but it's large enough to serve many other purposes. In case you don't use the full capacity of the pouch, there are webbing loops on the outside that you can use to lash the pouch into a smaller size with Paracord or elastic shock cord.

Measurements, approx:

Danish surplus

These are unissued and so fresh it's hard to believe they are a couple of decades old. The coating isn't flaking and the metal pieces aren't corroded. The only signs of old age are the manufacturing dates and the obsolete PLCE attachment system.