ACME Tornado Whistle Black ACT2000K []

This is the world's loudest whistle. When you breathe vigorously, a high-pitched tone that can be heard well and a low tone that resonates far away are emitted at the same time, and the sound reaches a wide range. You can check the tone in the video. ACME is a long-established British whistle manufacturer founded in 1870. The crew of the luxury liner Titanic also famously used ACME whistles.