This is an all-new product from the Raspberry Pi foundation, designed specifically for the Official Raspberry Pi 4 Case to provide optimal airflow for Raspberry Pi 4. The Official Case Fan comes with an 18mm*18mm*10mm aluminum heat sink with a self-adhesive pad improving heat transfer from the processor.
Features:

• 6-piece Acrylic case with access to all Ports on pi 4
• Compatible for All variant of the Raspberry pi 4 Model B
• Slot for Cooling Fan
• Easy to assemble without any Screws or Nut-Bolts
• Slots to route GPIO and CSI ribbon cable
• Cut-out for micro SC card at the bottom panel
• Mounting holes and anti-slip rubber feet at the back.