NOTE !! WILL NOT FIT TO OFFICIAL Ultimaker DUAL EXTRUSION UPGRADE !! slight modification necessary !!modelled for dual printhead design => BOTH AT FRONT SIDE!!!! WILL NOT FIT TO OFFICIAL Ultimaker DUAL EXTRUSION UPGRADE !!! Big advantage: you can close the sides of the UM with acrylic glasses without having to consider the fan duct space !! Alu-housing to be sealed with blue tape because of air gaps due to bendingSince I designing this, I mounted a dual printhead, a self-built heated bed and I closed the side windows... it works great... :-)