These balls are the very best toy for large, enthusiastic retrieving dogs. Never found better. I have two standard poodles who weigh in at 60+ and 70+ pounds, respectively. They can destroy a toy in seconds. These DuraFoam balls last even with the abuse my dogs give them. When one finally gets chewed up enough that it doesn't roll any longer I trash it and bring out another. These balls last for months before having to be trashed.