The Raspberry Pi Compute Module 4 IO Board for Raspberry Pi Compute Module 4 (supplied separately). It is designed for use both as a development system for Compute Module 4 and as an embedded board integrated into end products.
The IO board is designed to allow you to create systems quickly using off-the-shelf parts such as HATs and PCIe cards, which might include NVMe, SATA, networking, or USB. The major user connectors are located along one side to make enclosures simple
1 x Raspberry Pi Compute Module 4 IO Board