Now take a closer look on the GP pouch and the shoulder strap.
It can be closed by a YKK zipper, has a 2" YKK Velcro on the top for patches and further webbing on the lower part. It is 9" tall, 4" wide and 3.5" deep. Made of military canvas.
It can accommodate my Tibetan 375 Titanium mug easily, which holds my foldable Esbit titanium spoon, foldable Esbit titanium stove, Esbit cubes and has a Keith titanium lid.
This is the right side of the pouch. There is a Mil-spec elastic webbing and a 4" deep slide in pocket which, of course, binded.
Here is the left side, which is slightly different. The smaller slide in pocket is a card size pocket. It is great for credit cards, driving license, ID, etc. You can see the back of the Prym snap fasteners. There are four of them. They, and a military Velcro hold the pouch in place securely. The liner is a 70D kite fabric which is very durable and abrasive resistant, yet super light. The Hi-viz yellow helps you to find your stuff in poor visibility. Way much better than a dark colored liner around sunset in a murky forest.
Even the original pockets are very generous. My regular Esbit stove and Zippo lighter just sink to the bottom leaving lots of extra room above.
Here is the concealed pocket. It is closing also with YKK zipper. You see the left side where the fabric is bumpy. That's the problem in only a shirt. It is too close to the collarbone. I should have lower it with an inch or two.
This is a top view of the shoulder strap. There is a 2" wide Velcro as well. If you put your flashlight onto the last webbing from the top you can easily illuminate the track front of you.
All in all it is a great little bag. Well it's not that little (12x12x5" plus the bottle holder and the GP pouch). There are tiny things I'd done differently next time or on the customer's version which would make the bag even more comfortable and practical. But these are really just bits and bobs. However it offers you already a bunch of good attachment points, storage space and secure transport potential. Very comfy. You don't need more padding than this. Otherwise you would feel the bag wobbly. The Prym (german) snap fasteners and the Mil-spec Velcro hold the pockets so well, there is nothing to worry about. I've filled my Nalgene, put into the holder and shaking the bag vigorously. Everything has remained its original state. Both type of fasteners are certified for thousands of opening and closure. So, I'm not worrying even if I have to remove those pockets for a couple of times.