It's made for the USB RS-485 converter with FT232RL + SN75176. The XLR plugs are from AliExpress. I simply glued the module into the case, and the XLR plug is secured with 2mm screws. The lid is also secured with 2mm screws.

Links:

XLR: https://www.aliexpress.com/item/1005005716121082.html?spm=a2g0o.order_list.order_list_main.187.11531802oGkhqC

converter: https://www.gme.cz/v/1507873/modul-prevodniku-usb-rs-485 

https://www.aliexpress.com/item/1005006448907596.html?spm=a2g0o.productlist.main.5.37da6acarv9uEl&algo_pvid=0f821fe1-997b-4d32-89a5-0957ef987b52&pdp_ext_f=%7B%22order%22%3A%22112%22%2C%22eval%22%3A%221%22%7D&utparam-url=scene%3Asearch%7Cquery_from%3A