Abstract: The invention provides a new whistle, intended for sports referees, and for small boat emergency use, where a loud piercing sound is required without the possibility of loss of sound by "over-blowing" or by sticking of the freely-moving ball used in conventional whistles. The profile of the new whistle preferably is of flat-topped "mandolin" shape in side elevation, so that it is familiar and readily acceptable by established users, and yet includes three separate fipple-type whistle elements in a single whistle body, each with its own air column chamber and vibration-producing knife edge, at least two of which chambers are of slightly different lengths, so as to produce complex harmonics and beats that increase the piercing quality and audibility of the sound. This is done by providing two elements side-by-side and parallel to one another, with the third also parallel and below (or above in an inverted shape) the other two protruding into the space between them.