1. The lap belt is not padded and can be a bit uncomfortable at greater load
2. How are we really waterproof weatherproof or the whole? The main port is only to be closed by rolling, no Velcro, no zip, no studs, for once was not bad per se, if for at least enough material to curl would be present. But that is not the case and so the subject is closed fairly. Delicate items so I would not want to transport in the rain.
3. If you want to really take advantage of the volume, then you have to do without curling the opening, but unfortunately there is no way to secure the load, and even an existing tab is still too short for the longest setting. The backpack can be so loaded and standing open perhaps carry on a Dutch bike on the back, but not on a deep racing or similar ..
Had the backpack donated a lockable inseam of 20cm length, perhaps, then you could at least take full advantage of the volume and it would have been much more weatherproof. Just as the backpack but now once produced and sold, he has disappointed me, just when you wanted price. I will then times search for a matching backpack and these return again.