This is a dual fan duct for Prusa I3 using 40mm or 50mm lateral fans.
The item has three parts
1) the central holder (e3d v5 or v6) 30 mm central fan
2) the right fan duct(40mm or 50mm fan)
3) the left fan duct(40mm or 50mm fan)
This is a simplified version of the v2.0 made totally with FreeCAD
Sorry i missed this info :
Needs 4 screws M3 25mm long
2 fans 40/50mm left/right
1 fan 30 mm central
You might need also a zip tie in order to hold the hole system to the E3D barrel.
I have added fan guards modifing this :