Summary

Shortened by 10 mm, that's all!

This modification was made following my experimental findings which showed that an unshrouded fan gave the best reduction in warping. However, I noticed that most of the airflow coming from an unshrouded fan was actually passing above the printing area. This shroud is sort of a compromise to give broad cooling, while still giving it some directionality.

The diagram above shows how the shroud (blue) is aimed at the hotend (red), in this case a Ubis ceramic hot-end. You should only use it with insulated hot-ends, or else the extra cooling will drop your temps.