The wonderswan Crystal, was released in 2002.
It is essentially the same as the WonderSwan Color, except that the SwanCrystal uses a TFT LCD, superior in response time to the FSTN reflective LCD technology used previously. This gives the screen a much crisper look during gameplay, due to sharper contrast and significantly reduced ghosting.
As a result, the SwanCrystal does not possess the contrast adjustment dial found on the other models. Other notable differences are the four selectable volume settings (compared to three on previous models), and a face-mounted power button (compared to a side-mounted switch on previous models).