As described, heavy rubber, good quality. My golden puppy actually has very challenging time getting the treats out. I think an adult or adolescent dog might do better before getting discouraged. The ball with slits/nubs to hold treats doesn't hold much, but it still keeps her busy... the ball that dispenses the treats from inside, through a small hole, is a real challenge as the treats seem to be held in place with internal ribbing... almost like they need to step on it to release them, so it will keep them occupied.