Couldn't find compatible fan ducts for my Anet A2 printer, so I modified http://www.thingiverse.com/thing:1663551 by Elzariant. Raised fan mounting about 8mm. Made it with Tinkercad so it's not pretty, but seems to fit with little persuasion. Used original screws, but left the grill off. I'm not sure what the clearance to bed should be, so if someone prints this please give some input.