This is a case for the Open Source Sync Stripper (OSSS) device.

Project page for the OSSS is here https://github.com/bentika/Open-Source-Sync-Stripper

The OSSS is mainly designed for use with Extron Crosspoint devices that have many inputs, so the cases are "stackable" to support this use case.

BOM is 4 x 20mm M2 socket head bolts (to hold the case together) 2 x 5mm M2 flat head bolts (to attach to the adjacent case)