These are 3/8" thick tool steel plates for target practice. They are almost 6-1/2" in diameter and have a 3/8" mounting hole on one side. Bare steel, not painted. We tested these rigid mounted at 20' and they did hold up to a .308. If you put them out further and used a chain or swing arm they will last a long time against many different calibers. Great for plinking. Add a quick coat of paint and you will see how good you really are.