It seems I'm running behind the times, gear-wise with some of my collection, with finances being what they are, and being the primary income earner of a large household, but I snap up bargains and good kit where ever I can. This is one of those items I found being sold second hand, having missed their retail release. It is the Platatac WUP (Water Utility Pouch). I believe it has been superseded by the Accessories Small Flask pouch,which fills a very similar role, and has very similar dimensions
Sitting at 20cm (7.8") tall, and roughly 10cm x 10cm (4"x4") around, the WUP is the perfect size to take a 1L Nalgene bottle, as well as a variety of other kit, like night-vision scopes, bundles of cord, magazines or what-have-you. Think of the WUP as an oversized FUP, and you can see where my affection comes from.
Fitted with a big oversized top flap, that has a long double-tailed
webbing strap that comes over the top, and feeds through a webbing loop,
before terminating in a big Fastex-type clip.
The WUP also has a shock-cord and cord-lock drawstring closure around the lip of the pouch, which allows you to cinch it in to grip the top of your bottle, or whatever else you have in the pouch. An internal loop field allows you to secure the lid flap inside the pouch, the give you a rapid access option.
The WUP features two columns of three rows of PALS/MOLLE on either side, giving ample real-estate for fitting it with other pouches, if you really need, but more useful I've found for slipping a glow-stick or a pen through.
The pouch is fitted with the usual Platatac semi-rigid and press-stud MOLLE strips, and will feed through four rows of MOLLE, offering a very solid attachment. Something to consider when attaching a liter's worth of hydration, or however much the other kit you store in it weighs.
A grommet in the bottom of the pouch stops you hauling a liter's worth of pond-water should you take a dump, but this is where that shock-cord cinch comes in very handy for keeping a tight seal and keeping the outside, out.
I have really enjoyed having added a slightly larger pouch to my repertoire. Larger than the FUP, but not as big as either my dump pouches or the MEOP I also often wear, the WUP has given me somewhere to conveniently carry my watter bottle, but also keep a bigger range of items closer to hand than the FUP. Sometimes a bit bigger is just better.
So, if you find yourself browsing second hand pouches, and come across a serviceable WUP, I heartily recommend adding it to your collection, they work well on a Battle Belt or on the side of a pack.