Lovely made product, but sizing as mentioned before is a little off. Check on the Tatonka web site before ordering. This was too large for my 38l rucksack, so returned and bought the XS version, which fitted perfectly. Excellent product, love the attachment staps which allow you to permanently attach to your rucksack. Very waterproof as well, this with a Dry Bag inside your back and good to go into the hills.