Also known as a snatch block, these things arent cheap.
I got one recently and used it along with a huge tree to straighten my bumper, it was pulling my jeep with all four wheels locked up. My friend then put his jeep onto mine with a strap and it was moving both jeeps.
thanks for the bump. Not only are these things useful for multiplying the pull rating, but if you need to be pulled from an angle etc, very very useful.
obviously manufacturered in china, a company called Power Tool. I arranged a fairly large group buy of a whole bunch of stuff, got a couple items left over, trying to get rid of them. if you want to check it out let me know and we can arrange a time to meet up.