Haven't ever used one, I watched the video and they told me nothing. I have a full body harness. My teather line on the end has a weird looking metal hook. It has curls on each side of the metal. This is connected to a rope. From the video this rope is a moutainers line used to climb the tree. The problem is the rope is only about 4 foot long. I think its suppose to go around the tree but there is no way to fasten it so it will stay AROUND the tree. I know I am jus tnot seeing the whole pic here, can anyone help?