So these are made out of brake disks I cleaned up. They were caked with rust so I soaked in vinegar for a few days. Used a brush and the rust just slid off. Rinsed, dried then coated with some truck liner spray to protect the metal. Inserted a piece of 2 inch PVC in the center. This size fits perfectly around an Olympic style barbell. Then filled with concrete. Once dry I used epoxy and BBs to even the weight out. Original weight for each was exactly 35.01lbs on a shipping scale. I have made several weights like this and will post more eventually. All in all I’ve saved myself hundreds on just making myself weights.