120mm fan exhaust hood to 100mm exhaust piping

This is an exhaust hood that attaches to a 120mm fan and vents into a 100mm piping.

More details here: http://www.igorkromin.net/index.php/2013/05/26/a-clear-acrylic-box-for-the-portabee-3d-printer-part-1-making-the-box/