It is not a load binder although I guess it could be used for that. It is simply a mechanical hydraulic cylinder replacement mostly used like when one goes to an auction sale and you plan to purchase an implement and pull it home behind your pick up truck. Gives you an easy way to raise or lower the implement with manpower without needing tractor hydraulics.
Lots of people like me use them on older tractors that totally lack hydraulics (although this tractor does have hydraulics). It can also be used used as a poor man's tilt link in place of a hydraulic tilt cylinder when grading, boxblading, etc.
I think they can be bought for like $30 to $35 new. However, this particular one belonged to my grandpa in the 1970's, inherited by my uncle in the 1980's, inherited by my dad in the 1990's and finally inherited by me in the 1990's. The other three are gone now, but I remember all 3 of them fondly when I cranking on that mechanical cylinder. Actually it is not bad at all to use. I lower it once when I enter the field and then I raise it once when I exit the field.