This pack is much smaller than I thought it would be. The description is rather vague, and listed measurements for other packs are usually far less than actual when the bag is loaded...not the case with this pack. The side panel tapers from 6" on the bottom to 4" on the top, and the rear panel seems to have a slight taper also, making loading a large hard-sided object difficult if the size is too close to the size of the bag.
I would consider it to be a 1/2-day pack. It is hydration compatible without a bladder, and the water tube can be run on either shoulder harness with the provided elasticized straps. It has 2 internal mesh pockets on the front of the bladder pocket. It also 2 external mesh water bottle type pockets, although they are shallow depth, about 5". The pack material is polyester, possibly 600-D, and is relatively tightly woven, so could be treated with water-resistant spray with good results, if desired. There is no internal frame or side compression straps, so a snug load in the bag will help keep it from shifting. It has adjustable sternum straps which extend and slide up/down on the chest harness, as well as adjustable chest harness. There is no waist belt. The external front loops will allow for external lashing of additional gear, so this helps to make up for the bags smaller size of approx 850 cu in. On the reverse side of the front external loops there are internal loops to attach gear as well. The bag is top-load only with a draw-string closure and a double-layer fabric top cover with straps, though I would not consider these to be compression straps, as they are not anchored well into the top cover. Overall, it seems reasonably well constructed with a few weak points. I recommend that anyone considering this pack for purchase to first decide how much gear you intend to carry internally, and what you can lash externally before you buy this little pack. Also, will it be your main or auxiliary pack. It will stow less internally than the larger fanny packs. I bought it to use as a chest pack to extend the capacity of my current 3,400 cu in back pack, and it should work quite nicely for that purpose.
Check closely for defects...mine had a broken tab for the clasp (one of two per clasp) on a top cover strap.