PetSafe Busy Buddy Ultra Sub Dog Toy EXTRA LONG-LASTING PLAYTIME: Firmly holds 2 extra-thick PetSafe Busy Buddy Ultra treat rings to keep dogs motivated to play longer DURABLE FOR STRONG CHEWERS: Specially designed with tough nylon and rubber to stand up to aggressive chewing; dishwasher safe, top rack only TASTY TREATS: Toy comes with 4 natural rawhide PetSafe Busy Buddy Ultra treat rings; these irresistible treats are 4x thicker than regular PetSafe treat rings; refills available REDIRECTS CHEWING INSTINCT: Helps solve potentially destructive chewing behavior with hours of positive playtime CLEANS TEETH: Textured nylon nubs improve dental health as your dog chews SIZE INFORMATION: The Small size measures 3 1/4 in. L x 1 3/4 in. W and is recommended for dogs under 10 lb.; takes size D PetSafe Busy Buddy Ultra treat ring refills. SAFE PLAYTIME: PetSafe toys are made of safe, non-toxic materials. We hold our products to extremely high standards of safety and craftsmanship and design them with safety in mind. HERE TO HELP: Call, email, or chat with our expert US-based customer care specialists Monday through Saturday at 1-800-845-3274 or ccc3@petsafe.net; they are ready to assist you and your pet