A whistle (or call) is a simple aero phone, an instrument which produces sound from a stream of forced air. It may be mouth-operated, or powered by air pressure, steam, or other means.Whistles are used by referees to officiate at sporting matches as well as, military, and game calls. Here at Outdoor Shopping you will find the best whistles ranging from children key ring whistles, super loud high frequency whistle, multi function survival tool whistles, animal whistles. Great for police, dogs, survival, signaling, basketball, baseball, birds, football, Hockey, music, Track & Field, life guards, rave party, security guards, referee, youth sports, water polo, roller derby, rugby, soccer, adult sports, camping, fishing, hiking, rape safety, animal training, sports, gym. Commonly referred to as tin whistles, blare, hiss pipe,signal.