Fits many brands of hopper bins. Many outlets are called 16" and have 17-3/8" opening. Consult factory for your application.
Round collar is 17-1/4" OD and slips inside bin collar and cross bolts. Flat plate is Nolin standard 18" inlet plate and will bolt to any Nolin 18" square flange. For example, the adapter plate will bolt to a 18" rack and pinion gate.