Different brands and models! If there is an expansion port on your drum sound source, you can add a cymbal!

For example, Roland TD 1 1K has 1 expansion ports, and cymbals or drums can be added! (You can add drums or cymbals at will, and the timbre is optional). Roland TD 15K has two expansion ports, and you can add two more! Generally, in addition to buying an electric drum cymbal, you often need to buy an extra bracket, connecting rod and connecting wire.

Medley series DD 5 15, DD 5 16, DD 5 18 can be extended.