This backpack is really loaded with great features. Way too many to name here so just read the PDF flyer on Grivel web site. Before I get into the negatives let me emphasize that I have looked high and low and did not find a mountaineering backpack with better features. Now about the issues: (1) A major problem for me is that it does not fit my long torso. When positioned properly on my shoulders the hip belt ends up at my waist and there is no way to adjust that. In comparison, Deuter Guide fits well. (2) The tool carry sleeve on the back is too wide to accommodate axes with pronounced shaft bend (think Grivel Matrix and to some degree Grivel Air Tech Evo). The sleeve will force the picks to be pretty much horizontal so the tool shafts are in turn leaning towards each other (instead of standing upright), which precludes using the loops to tie down the shafts. The sleeve would work well with straight shafts. (3) For some reason the lid is cut slightly narrower than the back frame so it cannot easily cover the entire top of the backpack. The fabric of the extender tends to "leak" from under the lid. (4) The yellow fabric of the extender is very light and not waterproof and this fact, when combined with the previous bullet, is partially reducing the advantages of the great fabric used on the main body. Again, the review might come across as if I am slamming the pack but that is not the intent. If it fit my long torso I would still go for it.