Originally Posted by Diesel911

You use it to Saw off Limbs; wooden ones.

The high quality ones will also cut through Plastic, Aluminum and to a lesser extent mild Steel.

I have seen the cheap version aggressively nearly cut through a 6 inch Tree Root. I say nearly because the User ran the Saw against a rock and ruined it. the rock chopped off all the Teeth (the cheap ones have a sort of spiral wound flat Wire with teeth on each side; not very sturdy).