I think their worthless as well as the all the other little gagets they have come forth with since the 'Limb Saver' product. I have those on My bow and think I am receiving some sort of beneficial value from them. I just think that they have flooded the market so to speak to prompt sales which is the captalistic way! I dont think any of their stuff hurts anything except the string leeches are anoying at the shooting range with those thinps flipping of all over the place.B)