One-piece design. It’s secured with built-in long screws, so no extra parts are needed—ready to use right out of the box.

P.S.: The 8CM fan mentioned above is the Limin TL-8015 thin fan. Use a soldering iron to replace the original 4PIN wire with a 1.25MM 4PIN wire (available on Taobao; I bought the 10-centimeter version), and the wire connection order is shown in the diagram.

The system supports PWM speed control, so it’s much quieter than a standard USB fan even at full speed.