Has anyone used wire saw like this http://www.tinydeal.com/compact-wire-saw-px5kub-fth8032-p-9757.html ? It is said that it can be used for cutting wood, plastic, bone, rubber and soft metal.Is it really a useful great for emergency and outdoor activities? If yes, I want to order one for my brother who is a camping hobbyist. I need some professional tips first before I made my decision. Thanks in advance.