If you need to carry a bag on the mountain, might as well make it a doubly useful one. This Venom bag incorporates the Deuter Shield System which has a shock absorbing multi-layer construction to help protect your back in a fall. The padding is v-shaped and has spaces to allow air to circulate. There are anatomically formed hip fins and adjustable straps enable you to move  freely and get a comfy fit. It comes in 10 and 14 litre sizes.
www.deuter.com