The Ethernet Networking module for a Duet 2 Ethernet Board. It comes with standoffs and pin headers for mounting on PCB socket strips which are also supplied.
This is supplied as a spare part for Duet 2 Ethernet boards. Do not buy this product to convert a Duet 2 WiFi unless you are comfortable de-soldering the Duet 2 Wifi module without damaging the Duet. Be aware that converting a Duet 2 Wifi to Duet 2 Ethernet using this module will invalidate your Duet 2 WiFi warranty.