The life cycle of these Chinese manufactured balls has over the past 5-6 years been cur in half or even more. Yesterday using my trusty Chuckit Monster Sized Thrower a light chewer broke apart each and every one of these. Just a few years ago with a 135-plus pound German Sheppard who was a heavy chewer PLUS some they would last at least several days or more apiece. I will be looking for another product to use as I cannot afford to buy 4 or 5 packages of 4-Balls each week!