I've been using this every day since Feb 21 2012, and feel enough time has passed that I know the product well enough for review.

Construction*
It's made out of a tough Nylon sewn into tiny squares, which is known in the military field as rip stop fabric, although this is not labeled as such it is, how this works is if the fabric is torn because it's stitched in squares it will not rip open the whole thing or continue to spread, it will confine the rip to only the square or squares that are inflicted with the damage and prevent the rip from spreading, even after sleeping with it on, for months it still looks brand new.
It's build quality is higher than average, all zippers have enclosures they slide into to prevent rattling,and the band it secures with secures with Velcro, and an adjustable plastic buckle, the padding on its underside is soft and webbed allowing for airflow and less water retention, so you won't get as damp when your temperature builds up.

Measurements*
The pack portion alone is 5 inches wide, 3 inches high, and an inch deep.
I'm measuring this with it full, and with the front facing me with normal measuring tape.

With the whole thing removed and flat on a table it's 12 inches long which equals 1 foot and is adjustable within that limit with reason.

Application of service*
I've used this allot and tried everything I can think of with it, and here's the conclusion's I've come to.
It's very large, and in my opinion slightly awkward to have on a wrist, especially if you're going to wear it every day or even to bed in.
What I've found is that putting it on your ankle is AWESOME!, on ones ankle and full you don't even feel it, and I only take it off while swimming or in the shower, and with this method in place you don't even realize it's there and you still have your gear.
I'm using this for the following: Leather man squirt S "for cutting things and fingernails with the sharp blade like scissors", 16 band aids, 6 prep pads, a spare lighter, a spare house key, extra photon light batteries,a small fire steel, and three spare 44 caliber bullets.

I'm using this in combination with a cold steel push dagger and a photon micro light on a military neck chain, along with a powerful watch and the idea behind this is, that even when naked or walking around the house without my normal gear I still have the basics.

Fire, First aid, combat knife, utility knife, light source, back up power for light source, time/compass/ability to get bearings=watch set up, and an extra way to get back into the house/car/and rooms.

You never know, you could lock your house door by mistake while outside,lock yourself out of your room while in the shower, lock your keys in the car, cut yourself cooking, have a power outage, be assaulted randomly, lose your smoking lighter, need to trim your nails or open a package.

With this methodology in place I can respond instantly to any of those situations even if I'm stripped naked or sleeping without thinking or moving as it's all on me.

You could use it for a wallet or any number of things, but that's sort of what pants are for, unless a person wears something.. different?

Using pants with this totally conceals it also, so you always have your back up gear.
As a Marine, I feel naked without at least the basics and this works flawlessly for the applications I've assigned to this pouch which is last ditch survival/secondary.

Also it does tend to smell after a month of wearing it, I recommend hand washing it, and air drying, also some dollar store perfume will do if you don't care.

I've uploaded some pictures so you can see what it looks like after months of use and what it can hold.