The original set were very difficult to use, the weights stuck together and I had to pry them apart. I discovered that one of the weights was completely bent which was why that one was SOOOO hard to use. I called Sport Block and they sent me new weights and paid to have the old ones returned to them. They made the return hassle-free which I really appreciate and the new weights work PERFECTLY, the weights don't stick together at all. I do wish I hadn't had to go through the hassle of having them be so frustrating to use (before I had them replaced.) I am very surprised there is not a better quality control system in place with the company, but at least they made it right and I am very happy with the weights now.