1. Dividing and controlling the flow of hot air from your heater with valve; 2. Allowing one side to hot air than the other one or closing it. Outside diameter: 90mm Fitment: For heater For heater For Air Heater For 90mm ducts ducting Note: Installation guide not included, we strongly recommend you professional installation. Please check as much as possible to make sure the item is what you need. Tips: The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use Colour:black Material:plastic Package Contents: 1 * Parking Heater Joiner Connector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.