The Nina Ottosson by Outward Hound Tower of Treats is our most challenging dog puzzle yet! This Level 4 Expert treat puzzle is great for dogs who have mastered Level 3 dog puzzles and are craving an extra challenge. It keeps dogs busy with mentally stimulating treat-seeking tasks that activate your dog's senses and tap into their natural instincts to hunt and forage for food. As a result, our dog enrichment toys provide mental and physical exercise, help relieve stress, and reduce boredom for happier, healthier pups. Excellent for small, medium, and large dogs, the Tower of Treats involves complex actions that must be completed in a specific order; this encourages dogs to tap into their mental skills and problem-solve right before your eyes! Watch your dog use their brain to sniff out the treats, flip levers, spin the wheel, slide doors, and unlock drawers to reveal the hidden rewards! We recommend beginning easy with all layers unlocked, then upping the difficulty as your dog learns how to play. Since all dogs are unique, you can continue to vary the difficulty level of this dog food puzzle to meet your dog's problem-solving ability, with multiple ways to make it easier or harder for your pet. Moreover, this puzzle is easy to clean and made from food-safe materials that are BPA, PVC, lead, and phthalate-free for your convenience and peace of mind. Dog enrichment toys offer treat dispensing fun to enhance natural instincts like foraging and hunting, and keep dogs busy and entertained. Say goodbye to boredom with the Nina Ottosson by Outward Hound Tower of Treats!