The mini substrate designed for compute module 4 is suitable for evaluating CM4 or integrating into the final product. Standard for CM4 socket and color coded for 40 pin GPIO connector are suitable for compute module 4 LITE / EMMC series modules. Fan only supports 5V fan, not 12V fan. Please confirm the fan voltage before connecting. Applicable to all versions of compute module 4. On board micro-SD card slot (for version without EMMC). Interface: For 40pin GPIO Interface: USB 2.0 type A Interface: Mipi -2 (15pin 1.0mm FPC connector) Colour: blue Material: PCB Package Contents: 1 * CM4 Expansion Board 1 * Multicolor Row Needle Only the above package content, other products are not included. Note: Light 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.