8" x 8" Adjustable Blade Sidewall Ceiling Register Vent Cover Diffuser Heavy Duty Stamped Steel (Listed Size is for Duct Opening or Inside Measurement) The Listed size 24"x12" is

The Listed size 24"x12" is for inside duct opening measurement

This product has listed size 12“w X 10”h is for duct opening measurement only

This product has listed size 10''w X 6''h is for duct opening measurement only

the second measurement) is the height(vertical measurement)

If you measure outside or surface size

8" x 8" Adjustable Blade Sidewall Ceiling Register Vent Cover Diffuser Heavy Duty Stamped Steel (Listed Size is for Duct Opening or Inside Measurement) The Listed size 24"x12" isFirst thing to know about size selection: take the vent cover off the wall or ceiling. Measure the duct opening where the vent can fit in. Use the measurement to determine right size to buy. This product has listed size 8w X 8h is for duct opening measurement only, actual outsize overall dimensions is 10 wide by 10 high. If your duct opening size is 8 x 8, this is the right size and will fit in well. If you measure outside or surface size, you will