Dogs need exercise, both physical and mental, and puzzles provide stimulation and prevent boredom. The Challenge Slider dog puzzle from Nina Ottosson by Outward Hound is an interactive game designed to keep your dog active and engaged. An advanced puzzle especially for pups who have mastered levels 1-2, this level 3 puzzle will keep your pet's interest as they sniff, paw and nudge to uncover treats or food. A sliding tray has 24 compartments that holds up to 1 cup of food total. Insert the treats and slide the tray back into place, demonstrate to your pup how the puzzle works, then watch as your dog goes to work to find the treats. Made from food safe materials that are BPA, PVC, and phthalate-free. No removable parts and easy to clean with mild soap and warm water.