The Giant Run-about ball measures 11.5-inch in diameter. Now provide small pets with the freedom to exercise. Your pets can now enjoy the world around them inside these clear exercise balls. Encourages healthy exercise in a Secure and safe way Makes a great temporary holding area to keep your furry friend while you clean their home 11.5" diameter Recommended size for syrian hamsters, rats, gerbils, smaller hedgehogs and smaller chinchillas. Exercise balls can be beneficial and fun. The key is to use it SAFELY: Supervise pets at all times. Ensure you are using the correct size ball for your species. Ensure that your pet is ready for exercise and comfortable. Clean before & after each use. Make sure the ball is closed securely before use and has the proper ventilation slots. Avoid the sun, use only indoors in cool areas away from hazards such as other pets. Limit roll time, start with a few minutes per session and add on gradually.