Fan Duct Big Booster Hotend with 35x35 or 40x40 Fans

Fan Duct for Big Booster Hotend (J-Head shaft) from reprap-fab.org.
Hotend fan: 25x25mm + adaptor for 30x30mm fan
Component Cooling fans: 35x35mm or 40x40mm

Make sure to have ~1mm free space between the bottom of the cooler and the (inner) bottom of the main part.