1.[Compatible]for Raspberry Pi Compute CM4 stick is specially designed for Raspberry Pi Compute Module 4 CM4 and supports all CM4 versions. Documentation reference Geekworm Wiki search for CM4 Stick. 2. [Multiple expansion interfaces on board] Including 20pin GPIO/CSI/full size HDMI-compatible 2.0/USB OTG/USB2.0/Type-C/TF card slot/4Pin PWM fan interface, as well as restart and toggle buttons switch 3. [Use as a U disk] Connect the computer through USB-A OTG, and it becomes a real U disk. You need to use the toggle switch to set the mode and install the RPI BOOL tool, refer to the wiki: wiki.geekworm.com/CM4_Stick 4. [Power supply] 5V 3A is powered by the Type-C port of the CM4 for Raspberry Pi Compute Stick. It is recommended to use the official 5V 3A PSU for Raspberry Pi Foundation. 5. [USB does not work] CM4 disables the USB interface by default to save power. To enable it, you need to add dtoverlay=dwc2,dr_mode=host to the config.txt file. Product name: Compute module 4 IO expansion board 1 full-size HDMI 2.0 port 1x USB-A: OTG USB (for upgrading and updating Raspberry Pi Compute Module 4) 1x USB-AF: USB 2.0 high-speed interface, convenient for you to connect a keyboard or mouse. You can use third-party USB hubs to expand more USB ports. 1x USB-C: 5V/3A Type-C power port TF card interface: Micro-SD card slot (only supports CM4 module without eMMC) GPIO: 20Pin GPIO expansion interface 1x fan interface: 4P/1.25mm PWM fan control interface 1 x CSI Camera FPC Connector (22-pin 0.5mm pitch cable) 1x Boot Switch system boot switch interface (used when upgrading the system) 1x Toggl Switch (function selection for USB devices and CM4 devices) Compatible with geekworm 12mm aluminum alloy radiator C235. Working temperature: 0~80 PCB size: 70 x 45mm Material: PCB+Metal colour: blue Package Contents: 1 x Compute module 4 IO expansion board Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.