Size Guide

3.5" to 4" (89 to 101 mm): You will need a 4" x 10" device .
2.5" to 3" (63 to 76 mm): You will need a 3" x 10" device .

Before ordering, please measure the flange of your existing vent grille to determine which device size will fit.

How to Measure

1. Remove the grille
Take the grille out of the vent and place it on a flat surface.

2. Flip the grille over
Turn the grille upside down so you can see the flange that fits into the vent opening.

3. Measure the flange
Using a measuring tape or ruler, measure the width of the flange.

If your vent is larger than 4" x 10", please watch one of the guides below to see which option will work for your vent: