The CD's are designed for calming and acclimation to human-made sounds. Repeated playing of these music and gentle sound effects introduces your puppy to common noises. Set against the backdrop of bioacoustically designed piano arrangements, these soundtracks will accustom your pup to sounds foreign to sensitive and developing ears. CD1 includes common indoor sounds interspersed with clinically tested calming music. CD2 includes common outdoor sounds combined with clinically tested calming music.