Don\'t buy that shit. That entire leg strap system is shit. Its a very common piece sold on some of Chinese knockoff sites and it is shit. Let be more clear, I have it and its very cheap and WILL wear out in a month or so. I think I still have the stretched out piece of elastic nylon: I will post a picture to prove it. Also, the size length adjuster is not strong and will move and not stay locked in, which will cause a loss of your pulling force.
I cant speak for the penis attachment piece though. may be good, and may not. Let someone else take one for the team and then decide.
There are few very reputable and known sources for good hangers and stretchers already selling products. I would start there if it were me. Im happy to share all the crap I bought and what I think works the best if you like. Shoot me a message.