Simon Topman/Acme Whistle Co.
Stop! Thief!
Metropolitan Police Whistle (1883)
Designed by Joseph Hudson, Acme Whistles, 1883 to present
The innovation in this enduring design -- still in use by 120 national police forces around the globe -- is the sound that can be heard from up to two miles away, originating from its iconic barrel shape. The whistle can also be held in a police officer's teeth, freeing up his hands to nab more bad guys.