Fox 40 Classic Referee Whistle Mini CMG (Cushioned Mouth Grip). This is the one that changed the game! Authentic. Original. Fox 40's first patented pealess whistle. Same great whistle in a compact style. Mini whistle that has the Cushioned Mouth Grip (CMG). Used by referees and coaches at all levels who need every call to be heard. Flawless, consistent and penetrating sound keeps the referee in control of the game. Ensure every call will be heard!