1. Electronic organ: Electronic organ, also known as electronic keyboard, is a keyboard instrument connected with power supply or battery to produce music through electronic synthesis technology. There are usually various functions, such as automatic accompaniment, rhythm and melody, and various sound effects. Electronic organ is small in size, light in weight and easy to carry and store.

2. Electric piano: The electric piano is an electronic keyboard instrument. Compared with the traditional piano, it has lighter keys and smaller volume. Electric pianos generally have a sample sound library, which can simulate the real piano timbre, adjust the volume and control other music.

3. Folding piano: The folding piano is a foldable portable piano, which usually has 88 keys and some other functions, such as rhythm and timbre. The advantage of folding piano is that it is easy to carry and store, and it is suitable for traveling and moving.

In a word, there are obvious differences among electronic piano, electric piano and folding piano. Which instrument to choose depends on personal needs and preferences.