Solidoodle 2/3 E3D V6 MK4 fanduct
I used this http://www.thingiverse.com/thing:211657 on my E3D V5 and it worked wonders, but now i got myself an E3D V6 which is quite a bit smaller so i made my own version to acommodate the small size, but still maintaining the ability to use a 40 mm fan.