The Kool Kollar has many applications from using it for headaches, muscle aches, to just cool down. Great for wearing when watching outdoor sports, cutting the grass, or playing sports. They are great for pets too! The standard Kool Kollar comes with 5 distilled water ice cubes in them (pet size varies depending on the size of the animal). Simply freeze until you're ready to use, then just tied it on. Once thawed, just freeze again. You NEVER need to put them in water to use them (no crystals). Wide variety of fabric choices, including most sports teams. Hand wash and air dry to clean them.