Singing rounds has always been an easy way to introduce harmony to young singers. Now they can enjoy rounds based on the hit pop songs by John Legend, Anna Kendrick, Camila Cabello, Justin Timberlake and more! Each Performance Kit comes with 8 books and a code to access Full performance and Accompaniment recordings. Audio is accessed online using the unique code inside the kit and can be streamed or downloaded. The audio files include PLAYBACK+, a multi-functional audio player that allows you to slow down audio without changing pitch, set loop points, change keys, and pan left or right.