I bought the HHS adjustable strap that loops on to the tree and is adjustable. It has a prussik knot so its adjustable to all sizes of tree. The problem is the excess rope is a little long and hangs down a few feet. I think I'm going to pick up about 8 feet of Climbing rope for repelling and use the carabiner clips that come on the linesmans strap and tie it to those so it is a little easier to hang on the tree.

If you are only hunting a couple stands, I'd get what Ohio Novice is talking about. Then you are secure the whole way up and down the tree. I unfortunately have 25 stands up so I can't put one on all of them. I wish I was able to though.