The material used for the keycaps varies depending on the keyboard model and the language of the keycaps:
Dygma Defy
The Dygma Defy uses high-end laser-etched Cherry profile keycaps made of Polycarbonate (PC), which is more resistant than the traditional ABS.
Dygma Raise 2
The Dygma Raise 2 uses PBT double-shot keycaps for English US and UK and high-end PC laser-etched keycaps for dash and non-English languages, including dash keycaps. In both cases, the keycaps are OEM profile.
You can learn all about the difference between PBT double-shot and laser-etched keycaps in this video:
You can learn more about the different keycap profiles and how they affect typing in this video: