After trying just about every toy on the market - kongs, basketballs, soccer balls, softballs, firehose toys, etc., only to watch our GSD destroy them in seconds, we finally found the perfect toy. Called The Best Ball, Jax has tried with all his might. He can't destroy it. We got the 10 inch size: http://www.jefferspet.com/ssc/product.asp?CID=0&mscssid=SP7UJKAD22JR9MQDXL4KQN0485VA7JP9 Jax spends hours trying to find a way to pop it and he can't. We filled it with play sand to make it heavier. You can also fill it with water. Not to mention, Jeffers Pet has excellent delivery service. Dang, I don't know why the links to their site never work. Do a search under Dog supplies for "the best ball"