This is an Adapter I made for the Noctua NH-L9A-AM4 inside my Deskmini X300. The larger Fan improves Airflow to the VRMs and Ram. I printed it with PETG; no issues yet.

You will need:

• 120mm Slim Fan (NF-A12x15)
• 4 M3x4 Screws
• 3 M4x18 Screws

Side Note:
To make this fit into the original case you need to bent a tab on the backside of the case. You will lose the feature to lock the case with a padlock.