Paws & Pals LED Pet Neck Collar Flashing Color Light Up Night Safety Strap, Medium, Red DIMENSIONS: For pets with a neck circumference of at least 15 inches. Maximum is 19 inches LIGHT UP THE NIGHT: Adjustable and durable design conforms to your pet. Collar uses two (2) CR2032 3V Lithium Batteries MUST-HAVE: Easy to use, safe, and fun for your pet KNOW WHERE YOUR PET IS AT ALL TIMES: Neck collar comes in four modes: Steady, Fast Flash, Normal Flash, and Off. Easily keep track of your pet at night.