BIGTREETECH PI4B Adapter V1.0 for CM4 or CB1
biqu.equipment
The PI4B is a board that provides conversion interfaces to the CB1 core board to connect to your mainboard. It has a standard Raspberry Pi CM4 socket, fit for all versions of CM4. The function of PI4B plus core board(CB1 or CM4) is close to Raspberry Pi 3 Model B. If you want to run Klipper, this set is the most cost-effective set.

It’s basically an OrangePi as far as origins go, but has the same form factor, and can be used in the same places where the Pi 4 Compute Module can.

They also sell these nice pads: https://biqu.equipment/collections/lcd/products/bigtreetech-pad-7 – That basically take the CB1 (CM form factor) and integrate it into a display for 3D printing.

This all comes from my little corner of the SBC universe :)