Description Features: 3 types for your option: 55X40mm/56x41mm/55x40mm. Mini base board designed for Raspberry Pi Compute Module 4, suitable for evaluating the Raspberry Pi CM4 or being integrated into end products. Standard Raspberry Pi CM4 socket and color-codedRaspberry Pi 40 pin gpio header, suitable for Compute Module 4 Lite-/EMMC series module. Onboard multiple connectors including: CSI-/DSI-/HD-MI/USB/RJ45/Micro- SD-Card Slot. FAN fans only support 5V fans, 12V is not supported, confirm the fan voltage before connecting. Specifications: Material: PCB Size: approx 55X40mm/56x41mm/55x40mm(optional) Type: A/B/C(optional) Note: Please allow 1-3cm error due to manual measurement. please make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Expansion Board Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.