Ok this is the most useful toy I have found.  Not only can you let them destroy them, but then you can recylce one you are done.  Aleast I have.  Emply water bottles, without the lids of course.  Not only do they slide across the floor,which means chasing things around, but they make a lot of noise.  Both of my dogs love them.  When I picked out my lab with the breeder, this is what was in the kennels.