Grover-Trophy Slide Whistle. Music is a very important aspect of early childhood development. Great way for pre-school and elementary students to learn how to make music. Brightly colored and extremely durable TROPHY slide whistles are the easiest of all novelty instruments to play. Simply blow in the mouthpiece and move the slide to produce an amazing glissando (trombone) effect. Nickel-plated steel. 12-1/2" long. Assorted Colors Available in Red, Blue, Purple, Yellow, Orange (Sent Randomly)