A set of two or more whistles. Each whistle of the set sounds differently from each other based on a different type of sound or a different value of a characteristic of sound common to whistles of the set. Sound characteristics may include but not limited to pitch, quality, loudness, and/or duration. Each whistle in the set may be different in appearance from each other in the set. Appearance characteristics may include but not limited to color, numbering, design, light up features, size, and/or shape. Alternatively, the whistles in a set may have a common appearance characteristic, but each whistle may have its own value of the common appearance characteristic. Additional element(s) such as lanyards or mouthpieces may be added to whistles of a set to distinguish them from each other. The set of whistles may be included in a kit having a box for removably storing the whistles.