Bone Replacement Parts for Dog Puzzles are for select Nina Ottosson dog puzzles. These dog bones are for replacing damaged or lost bones from the Dog Brick, Dog Smart, and Dog Tornado games. Each pack comes with five bones to keep your pup puzzling and practicing their nosework! Simply place bones over treat compartments in Nina Ottosson's Dog Brick, Dog Smart, or Dog Tornado games. Dog puzzless are great for mental stimulation for dogs and dog enrichment by testing your dog's problem-solving skills. PLAY BY THE RULES – SAFETY & CARE: When choosing a toy, make sure to choose an appropriate size/style/level for your dog. No toy or game is indestructible. ALWAYS supervise your dog closely, teach your dog how the game/toy works. Do not leave the dog alone with a treat game/toy, do not let the dog chew on the game/toy or pieces. Inspect regularly for damage and remove if broken, or if parts become separated, as serious injury may result. For dogs only, not a children's toy. When empty, store until next supervised use.