OFG brings up a very good point. You want to make sure the finish on the weights is very high quality. Since inserts dry, crack, fall out, cut line, I could go on, but you want to avoid inserts. You also want to make sure the insert free ones are finished in a manner that doesn't fray lines. It's easy to test, just have someone hold a stretch of low test line with a weight on it, then just run the weight back and forth really fast while turning the weight in your hand. Any fraying means its not a properly finished weight. I found the original manufacturer of the tru-tungsten weights, which I've always preferred. I've been thinking about making a video showing the fray test, but wasn't sure if people would be interested in watching it.