These extruder parts will allow direct mounting of the Phaetus Dragon hotend on your Prusa MK3S.
This model guides the airflow from the hotend fan to the central section of the Dragon, where it's needed. Without this, much of the cooling airflow bypasses the cooling fins, and cooling isn't as effective.
This also adds a locating tab to prevent rotation, allowing for one handed nozzle changes. Nice!
There are two versions of the inner duct included. If you're not doing a full teardown of the hotend, print the Extruder Cover and the Inner Duct. The inner duct can be slid into place and glued to the existing Extruder Body so you don't have to take everything apart.
If you've already got things torn down, go ahead and print the modified Extruder Body as well, which integrates the air guide into the base Prusa part.