What Lamar said was true, but remember, if you use the rounded blade that is sold by lure making supply stores and attach it via split ring, you have nothing to worry about. The patents deal with the shape of the blade and the way it is attached directly to the head, that is why everyone stopped selling the shake heads with the open line tie to attach a blade to it, because that method is a patent violation. I personally like the split ring, the down side is I lose a little of the noise since the blade doesn't hit the head much but that is about it. The up side is the hunting or searching action I get, my baits run left then right then up and down and they made not be loud but the vibration is incredible and that vibration combined with the erratic action make them a killer, and I believe better, than an original chatterbait.