- Outside overall dimension is 13.75" in length and 10" in width
- Duct opening - a hole that holds the duct neck to allow air to come out from HVAC system. This register fits in a duct opening of 12" in length and 8" in width.
- Measure the size of the air duct opening(the size of the "hole" ) .
- Measure the duct opening
- Match the duct opening size with the listed size of 12" x 8".