The CTK-520L was the first model to feature the Key Lighting function with red lights that illuminated the keys themselves (white and black alike) on a standard keyboard approximately the same size as a pianos, using the lights to guide the user to the keys they should press in order to play 40 built-in songs. It also featured a three-step lesson system allowing the user to follow the lit keys to practice at three levels of difficulty. Overturning the stereotype that one cannot enjoy playing a musical instrument without lengthy, repeated practice sessions, the model was an innovative keyboard allowing even beginners with absolutely no experience playing musical instruments to get a taste of the joy of musical performance right away by following the illuminated keys.