This Propex directional vent is used with either 60mm (for HS2000) or 76mm (for HS2800) reducers to connect to the outlet ducting of the heater install. You would use this vent in the case that you want more than one vent in your installation. Use of a reducer is required.
You can find reducers here:
Ducting Reducer for 60mm HS2000 & HS2211
Ducting Reducer for 76mm HS2800
