The Raspberry Pi 4 Case Fan is an official accessory for Raspberry Pi 4, intended to be used in conjunction with the official Raspberry Pi 4 Case. Designed for over-clockers and other power users, it keeps your Raspberry Pi 4 at a comfortable operating temperature even under heavy load.

Features:

Fits perfectly into the lid of the official Raspberry Pi 4 Case
Temperature-controlled fan delivers up to 1.4CFM of airflow over the processor, memory, and power-management IC
18mm × 18mm × 10mm heatsink with self-adhesive pad improves heat transfer from the processor

Specifications:

Input voltage	5V DC supplied via 40-pin GPIO header on Raspberry Pi 4
Fan speed control	Pulse width modulation control via user-selectable GPIO pin
Maximum airflow	1.4CFM
Case Material	Clear PC

Fitting Instructions:

Insert Raspberry Pi 4 unit into the lower half (base) of the case, taking care to first remove any SD card, and to align the connectors with the apertures in the base.
Insert the case fan into the upper half (lid) of the case, with the fan pointing away from the lid. The two tabs on the fan housing should fit neatly into the inside of the tabs on the lids, and the slightly curved edge of the housing should be flush with the underside of the lid.
If you are also fitting the heatsink, remove the backing paper from the self-adhesive pad on the base of the heatsink, position it centrally over the processor and gently press it in position.
Connect the wires from the fan to the Raspberry Pi 4 40-pin GPIO header as follows: