What happens is the string cuts through the leech. Here is how I solved the problem. Take 2 pieces of 3/4" length of rubber peep sight tubing and slit it lengthwise. Now wrap it around each half of the string and install the leech between them. To help visualize what I mean think about the foam insulation used on water pipes. It is a tube of foam that is slit lengthwise and installed over round water pipes.