The Fox 40 Classic CMGis cushioned to enhance the original Fox 40 Classic whistle; Cushioned Mouth Grip (CMG®) thermo-plastic material provides superior grip and protection for teeth.Ideal for those who need to hold whistle in mouth for extended periods of time. Flawless, consistent and reliable. Easy to blow and cannot be overblown. Will be heard above ambient noise, loud crowds, the roar of engines, breaking waves and thundering gale-force wind. Sound will be heard up to a mile away.