Yamaha PSR-J21

Yamaha PSR-J21 is a portable keyboard designed for beginners and hobbyists. It is a 61-key keyboard with a range of features, including a built-in sequencer, a variety of voices, and a range of effects. It has been used by many musicians, including John Legend, who used it to compose his hit song "All of Me".

The PSR-J21 works by allowing users to select a voice from the keyboard's library and then play it using the keys. It also has a built-in sequencer, which allows users to record and play back their own compositions. The keyboard also has a range of effects, such as reverb, chorus, and delay, which can be used to enhance the sound. Additionally, the keyboard has a range of accompaniment styles, which can be used to create backing tracks for songs.