3 mm boom and brackets
thingiverse
This fan duct prototype (http://www.thingiverse.com/thing:190298) features a boom and bracket system to attach the duct to the hotend. However, I found it unstable and not reliable for that purpose. Nevertheless, someone might appreciate using the leftover boom and brackets as an additional accessory. Please note that the brackets are 3mm thick, not 4mm as previously mentioned. A photo is attached for reference. The description has been corrected.
Download Model from thingiverse
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