I needed to make a block and tackle system that I could use to lift my deer feeders high into the trees. This is what I came up with. The frame is designed to prevent the paracord from slipping off of the wheel and the body is designed to be well fitted so the rope cannot slip in between any spaces and get jammed. This is a double sheave design so it will give you 4 pounds of lift for every one pound of pull. This can be modified to hold three sheaves (just use an additional center piece with another sheave) and that will give you 6 pounds of lift for every pound of pull. This has been tested at 150 pounds without issue. I am confident it will lift a lot more but you do so at your own risk, as I have not tested it. View it in action here: https://youtu.be/Aj3af8e8Vz0I printed this with a 50% infill. I would not go below 30% but I guess you could if you were making this for a very light lift. Use this item at your own risk. Parts: (4) 2.5" long 5/16-18 bolts (2) 2.5" long 1/4-20 bolts (these are for the pulley sheaves -aka: wheels) (4) 5/16-18 locking nuts (2) 1/4-20 locking nuts