Fox 40 Classic Finger Grip Whistle is used worldwide for sports of all levels and features a padded finger grip for added safety and comfort. Authentic.Original. This is the one that changed the game! For referees and coaches at every level who want every call to be heard and depend on it`s reliability. Flawless, consistant and penetrating sound keeps the referee in control of the game. Be heard above the crowds and players. Standard choice for personal safety and rescue professionals worldwide. It will be heard above ambient noise, engine roars and breaking waves. Chambers are designed to self clear when submerged in water.No moving parts to frezze, jam or deteriorate.