I recently started caring a whistle on duty after responding to a call with our local police department. Part of their required uniform is a traditional whistle. Well we could not find our pt because they were down in a drainage ditch with our pt. PD doesn't have direct channels to talk with EMS so all of a sudden I hear 2 whistles 1/2 mile away. After that I am sold on keeping a whistle on duty, low-tech never fails. A $6 whistle did what a multimillion-dollar radio system could not do, connect responders. A whistle will work in a dead spot, never run out of batteries, or ever have a burnt out light. Plus it is light to carry.