The ACME Tornado 2000 whistle has a clear, penetrating blast that is guaranteed to give you total command of the game. The extra high frequency of the ACME Tornado Referee Whistle hits heights not reached by any other whistle. This higher pitch gives greater penetration and creates a crescendo of sound that cuts through even the greatest crowd noise and makes it a great choice for sports officials and referees around the world. Two ultra high frequencies to cut through background noise. Made from the latest high-tech plastics with the most advanced techniques and 130 years of whistle making experience. Metal fingergrip has rubber cushion and is adjustable. Fingergrip whistles were invented by ACME in the 1890's.