This backbag is designed for cyclists, but in reality could be used by walkers/hikers. What attracted me was the Deuter 'Airstripes' cooling system. I have had previous backpacks which claim to not cause you to have a sweaty back, and do. I use mine for mountain biking so that was important to me. Additionally the straps are a webbing design which is designed to reduce sweat. Does it work? Well don't know yet as I have only used it once on a short (3 mile) road ride, in quite cold condtions. However the design does look like it will allow a good air flow, so bodes well. Will up date once I have done a few longer off road rides in the summer. The Deuter X Race claims to be 12 litres and it is certainly plenty big enough for me. I can pack a light-weight jacket, over-trousers, inner tube, pump and a few other small items inside the large compartment, which also contains a smaller netted pocket which has its own zip. Still room for more items. Should be able to get sandwiches in there as well!! There is also a larger 'slot' for holding a hydration bladder. I use it with a Source 2 litre Widepac which seems to work well and is cheaper than the Deuter Streamer. On the out side there are 2 separate pockets both zipped. One at the top. Quite small but big enough for a large mobile phone and other small items. The second pocket is on the back and is longer and slightly larger. There also 2 webbed pockets on the out side, both quite small but would take a 500 ml water bottle (if you are not using a hydration bladder or bottle holder on your bike frame). At the bottom of the bag there is another zipped pocket which contains a bright green cover. This is a nice touch, but suggests that the bag is not water proof. The pocket is quite big and would take another item such as an inner tube or more if you ditch the cover. I will probably keep and use to protect the bag when I get out on a muddy trail... Other features are a small band on the back where you can clip a rear light, and is also reflective. The words 'Race X' are also reflective, but personally I would have liked some more reflective bits to increase visibility at night. Inside the back pocket there is a clip where you can attach keys. The toggles for pulling together the zip for the large part of the bag can be attached with a stud, which ensures that it will not open accidentally. There is a velcro strap on the right shoulder strap to fix a pipe from your hydration system. The straps themselves are clip type and of course fully adjustable. I found the bag comfortable, but stress I have only tested it for 3 miles, but the bag is very light. In summary I do love this bag. It seems well designed and looks strong. Only time will tell. The only downside is the price! I paid £40.51 (including delivery) at Outdoors GB, which is the cheapest I could find on internet (slightly cheaper than Amazon). I wouldn't normally pay this for a backpack however, I do tend to think every thing is overpriced(!), and my first impressions are that it is excellent.