The Fox 40 PearlTM is perfect for those who don't need a loud piercing shriek, yet want a blast above man-made and environmental noise Optimal choice for elderly security and child safety, or wherever there is a need for a distinct sounding whistle Different lower tone is ideal for multi-field games 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 Chambers are designed to self-clear when submerged in water Will be heard above ambient noise, loud crowds, the roar of engines, breaking waves and thundering gale-force winds