These part cooling fan ducts have been modified to use bolts to secure the part cooling fans instead of the peg and friction fit of the previous versions. This is compatible with RB1, RB3 and RBB3 printers with the dual extruder upgrade.
To secure the fan to the duct, use either: 22mm M3 bolt (x1) and 3mm nut (x1), or 8mm M3 bolt (x1) and brass insert.
As with all our printer parts these are precision parts. For best results it is highly recommended that you use calibrated filament using the method found here: https://www.thingiverse.com/thing:1037301