This is a fan mount for the Protectli VP6600 series of firewalls. This is indexed to fit the fins on the VP6600 series and runs very quietly with the fan model linked below. As this removes a lot of head, an average of 35f from what I read on the CPU sensors in OPNsense, you can print in PLA if you wish.

Noctua NF-A14 5V: https://www.amazon.com/gp/product/B07DXP4251/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

This fan comes with all the parts you need to attach to an open USB port on the device to power the fan.