Excellent design. Perfect fit for FFCP or PowerSpec printers with this head config. Provides excellent airflow to both nozzles. More importantly this duct allows for more clearance/ nozzle height adjustment. Stock duct doesn't fit when glass is added to the bed and the nozzles are raised. This works perfect.
-used supports under large fillet (although not necessary, can provide better finish
-ABS, glass bed with abs slurry