Are you imagining a custom installation of your Propex heater ducting?  This Y-junction allows you to create a branch for a separate outlet to distribute your heater output.

Fitment notes:

• Must be used in conjuntion with either the 60mm adapter (for HS2000 and HS2211 heaters) or 76mm adapter (for HS2800 heaters) to connect to your ducting.
• Add some vents!  Choose from a fixed directional vent or a vent that opens, closes and rotates.