120mm x 120mm x 100mm high.
4.5mm diameter holes, suitable for M4 Fasteners. The holes are counterbored for a M4 washer. (Not shown in my photos)
I printed mine with:
0.3mm layer height
3 solid layers
Feel free to reduce the layer height, however this will increase the print time, and it's a long print.
It has been mounted in a cantilever position with the weight of the ducting hanging off of it for 6 months now, and hasn't had any problems.
If you can check your gcode before printing, ensure that the 100mm cylindrical section is printed as a solid wall. I reduced the wall thickness to 1.35mm in this model to allow the wall to be printed in ~3 perimeters. This should reduce the printing time from the original version which printed the inner and outer walls as two concentric walls with a small gap between them.