The internal structure of the A-Plus FFU cabinet consists of the FFU cabinet, the fan base plate, S-Guard, and the lower partition board.

1. FFU cabinet: It serves as the load-bearing component and provides space for converting the dynamic pressure of the fan into static pressure.
2. Fan base plate: It supports the fan.
3. S-Guard (divergent plate): A involute air duct designed based on Archimedes' spiral, minimizing the resistance to the airflow.
4. Lower partition: It replenishes the pressure in the static pressure vacuum zone below the fan base plate, improving the uniformity of wind speed.