Its so that you pull out the light line to the tree, put a block on it, bring the light wire back to the winch and let the light line pull the heavy line to the tree (so you can work with 3/16ths line vs the 7/16” or 1/2” main line).
Aaron Z
Ok now I'm getting this a little betterah, thought for a min I'd have to youtube it. Suppose that could be helpful in repetitive long distance uphill winch line pulling vs trying to pull winch cable up hill by hand or someones elses hand, it would be too much work for me.