This is an ABS fume reducer built to plug in to the MK6+ extruder frame. The MK6+ extruder frame forms a natural "vent hood" when you block off the sides with clear tape. This filter reduces the ABS fumes by around 80%-90%. The hood seems to be very efficient at picking up the abs fumes, but some of the fumes make their way through the filter due to the coarse nature of charcoal filter that was used. The tubing used is sold by the yard from a big-box home improvement place and is between 30-31mm in diameter at the narrower "plug-in portion".Warning! The filter holder and tube connector are both at or slightly larger than the print size limits of the TOM. In order to print these, I had to sand out divots and square out the lower corners in the front frame of the TOM so that bolts at the front of the ABP and the lower corner of the ABP would not hit the frame (see the divots taken out of the frame in the second image). You can insure that your adjustments are working by manually moving your build platform such that its acrylic sides are just brushing against the TOM front frame (the bolts on the left and right sides of the ABP should not contact the TOM frame). It is also important to re-calibrate your TOM before printing these to insure you are operating from the exact center of the print surface.The 12V fan used is about 91.5mm square and was recycled from an old PC. The fan is powered from an unused TOM 12V power supply connector (the connector with the black/yellow wires is 12V where yellow=+ and black=-).The charcoal filter is 3 layers of litterbox filter from a pet store.The gen2 version of this thing will include a different filter medium with a finer grain. The vent-hood design will remain the same.You can see the second generation version of this filter here: http://www.thingiverse.com/thing:18483