Pre-Drilled Urethane bowling balls. These are the same great super durable bowling balls that you see at the bowling alleys for you to use. These balls are meant to take a beating and keep on rolling. No need to worry your kids will break these balls. These balls are also great for adults that need to use an 8 lb bowling ball. Each ball comes with the weight engraved, pre drilled and ready to use right out of the box.