When you try ION's all new Transom series, you will get blown away, literally. This ION exclusive feature creates airflow by shifting the backpack away from your back when going uphill. For going down just release the system and pull it tight. Not just bla bla, it really works!.With 16l capacity, this backpack carries all your stuff for a whole day: up to 3l water reservoir, tools, pumps, tubes, additional rain jacket and jerseys for changing, protectors, bars, and loads of candy. Of course you can fix your helmet, too. You need more space? No worries, the Flex_Panels let you pack even more of these yummie...By the way: the slick design using a special coated, lightweight ripstop fabric enables you to remove what your rear tyre left on your rucksack.