The Fox 40® Classic™ is the standard choice referees and coaches at all levels, rescue professionals and general safety worldwide No moving parts to freeze, jam or deteriorate Flawless, consistent and reliable The harder you blow, the louder the sound 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 winds Chambers are designed to self-clear when submerged in water Sound will be heard up to a mile away