Acme Tornado 2000 Black Plastic Whistle. As used in FIFA Internationals, Premier League and Champions League. This is the world's most powerful whistle, featuring two high-pitch frequencies for volume close to the whistle and a lower pitch for long-distance sound. Recommended for referees, big stadiums, or wherever real power is required. Specifications: Dimensions: H:14.5 x W:7.0 x D:2.6 cm. Model Number: FB530.