10" X 10" [Duct Opening] 4-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 11.75"W X 11.75"H] 8" Round Duct Pipe Design – These Supply Diffusers RG2230 HP w4h4 const modal document

Design – These Supply Diffusers with integral round necks are recommended for heating

ensuring it fits most standard thermostat models

actual front end outer dimensions are approximately 27 5/8" width X 28 5/8" height

designed for optimal airflow and efficiency

+ Product Details Size - 18"w X 36"h is the size for the duct opening measurement only

10" X 10" [Duct Opening] 4 Way Air Vent Adjustable Aluminum Curved Blades Integral Multi Shutter Damper HVAC Diffuser [Outer Dimensions: 11.75"W X 11.75"H] 8" Round Duct Pipe Design – These Supply Diffusers RG2230 HP w4h4 const modal document Design – These Supply Diffusers with integral round necks are recommended for heating ensuring it fits most standard thermostat models