Petzl have produced a backpack for sport climbing, called 'KLIFF'. It's a simple, well thought-out bag which is ideal for the climbing wall or the crag.
The KLIFF bag is a simple, lightweight backpack for sport climbing and carrying your kit to the wall. It’s capacity is a generous 36 litres. A single zip opens the main compartment, where you can easily get to all your gear. I prefer being able to access everything like this (it’s much easier if you can see your kit straight away!) and the features are neat and well thought out.
The main compartment is big enough for a standard day of sport climbing, or trad climbing when you chuck the rope over your shoulders. The zipped top pocket is useful for smaller items (tape, sandpaper, phone, keys, a couple of bars etc).
The backpack includes a detachable rope tarp, which is good for keeping your rope out of the dirt and dust. I keep it loose, so I can cart the rope around at the crag.
The shoulder and chest straps are comfortable for using this as a sport pack, but I’ve been meaning to attach a waist belt so it’s more comfortable for longer walk-ins, if I have a lot of kit, or if I use it as a trad bag.
I was concerned about sharp items poking me in the back (there’s no padded back system), but as long as you put a jacket in last/at the top, you’ll be fine. It’s good that the underside of the bag is a tougher material, as this is what sits on the ground. It’s also advantageous that the back system (basically, the shoulder and chest straps) don’t get put in the dirt.
A couple of photos from Petzl:
Here’s some photos of the bag in it’s natural environment: Ceuse!