Dueter external pockets
These came nicely packaged and in plenty of time. I bought them to have extra readily accessible storage for my Lowepro sling, which is going to serve as a daypack for some of my photographic equipment and personal items on an upcoming trip to Iceland. The pockets have two rows of loops about 4 inches apart running the length of the pocket. I attached one of the pockets to the strap of my Lowepro sling with two narrow velcro straps. Into the pocket I stuffed: *a knee length rain cape in it's own pouch * a large waterproof cover for a backpack (or Lowepro sling) * a waterproof camera cover There was enough room left over for lens filters, cleaning cloths, or maybe a candy bar and a few other things...in other words, lots of room! I could attach these pockets to a carry-on, a backpack,or to the strap of my handbag. (Good for plastic baggies, dog biscuits, water bottle, collapsible cup...endless possibilities!) I'm not positive they're waterproof, but so far, I'm very pleased with this purchase.

creates two packs in one
When going on a ski hut trip you really need two packs. You need a bigger one for the hike in and a smaller one for day skiing. At first I used my big pack and it was great for going in and out but was way overkill for the day work. Last year I tried a small daypack with a lot of lashing and strapping of stuff to the outside. I looked like the junk man and the stuff did not carry well. The Deuter External Pockets solve a problem. They convert a day pack into an effective higher volume pack for the hike in and out but you can disconnect them and leave them at the hut for the day excursions into the powder. There is no rocket science here. The size is good (maybe could be a tiny bit bigger), the construction is not overkill so the weight is reasonable. I use 3 or 4 depending on what I am taking.

Very useful pockets
I really love my Deuter ACT lite 50+10 backpack, but sometimes I just need a little extra space and having quick access to things like gorp or binoculars or bug spray is really handy. These pockets seem as well made as the pack and easy to attach to the side compression straps. Even with the pockets attached I can still use the side compression straps and bottom pockets for my fly rod on one side and tent poles on the other. My only complaint is that they only come in black, but they work so I can live with that.