The Fox 40 Classic Pealess Whistle has no moving parts and creates a flawless and easily heard sound that is ideal for coaching and use by referees. The Fox 40® Classic® is the standard choice referees and coaches at all levels, rescue professionals and general safety worldwide. 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 winds, Sound will be heard up to a mile away