We bought a few of the Westpaw toys. At first, our 9 month old Havanese didn't quite like them as they were not chewy enough! Last week, we put a large Kong Treat in the Twiz and this toy has now become Cooper's favorite toy. He finds it extremely challenging and frustrating to get the treat out (harder than in a Kong toy). We have now found in Twiz a toy that keeps our dog happy for long periods of time.