I love these balls for my new ball machine. I chose these over Gamma brand, based on a small price difference. Elsewhere I read a review of these Penn balls being "hard as rocks"; that is not the case. They are pretty similar to pressurized balls. If you get a new ball machine, check the instructions to see if you need a break-in period with old balls; I did, so I had to wait before I could use these new balls. Highly recommended!