I just saw those the other day in the new issue of Bowhunting world. We were talking about them at work. One of our concerns was also what it would do to your bow over time. I am sure that if the bow company of your choice wouldn't back a warranty if they knew you had it on the bow. when I did a dealer search I saw that one of our local pro shops was listed, and Dick's Sp. Goods was also. My wife and I will be Christmas shopping this weekend and will be at Dick's, so I am going to check them out. I am anxious to see the cost on one. Probabaly not real cheap. It would be fun to set up one of my older bows with one.