User Review: REI Flash 18 Pack

The shoulder straps are a very thin material and completely perforated. This is great for weight, and perhaps not so great for your shoulders. However, if you ever find yourself carrying enough that these straps bother you, you might be carrying too much (my guess is more than 15 lbs).

There is no structure to this bag in the form of a frame, padding or otherwise.  This should be fairly obvious from other reviews and the description of the bag on REI's website, but it is a consideration worth being clear about. As a consequence, the water resistant material sits directly against your back making it difficult for your the sweat there to evaporate.

All that sounds like a negative review, I know -- but I really like the bag, and I like it much better than the Flash UL which it replaces.

The bag is shaped somewhat so that if you have it stuffed to capacity mostly with flexible items (i.e., extra layers, shell, etc...), it will place much of the weight close to your body. Mind you, this is not physics defying, but it is thoughtful and is different than its predecessor, the Flash UL, which being shaped like a flat-bottomed sack, allows the contents to sag away from your body moving the center of mass inches away from your spine and lower than on the Flash 18, pulling harder on your shoulders than is necessary for a given weight. 

Don't stuff either to capacity and the math on this is inconsequential. However, it is a bit of a teensy-weensy bag, so capacity is closer than not.  Max that I have fit: 200 weight fleece quarter zip, 700 fill-power down vest, rain shell, fleece hat, 4x5x3 soft-sided first aid kit, 3-liter water bladder, sunscreen, bug dope, quart ziploc of trail mix, 2 Clif bars, sandwich, and the "box" (4" high, 5" diameter screw-on lid tupperware).

It can totally fit in your main pack turned inside out and (per REI suggestion) used as a (big and slightly awkward) stuff sack, or just scrunched up into an unnoticeable ball.

Full price (around 30 bucks) seemed a touch expensive for an unstructured sack, but I haven't found anything to compare it to given its light weight and crushability...due entirely to the fact that its unstructured.

By the by, the ripstop material works.