Broan QTR110 Ultra Silent Bath Fan, 110 CFM 4-Inch Ducting Size 110 CFM and nearly silent operation 1.5 Sones 4-Inch ducting Motor engineered for continuous operation UL Listed for use over tub/shower with GFCI circuit Housing Dimension: 10-1/2-Inch by 11-3/8-Inch by 7-5/8-Inch - Fits 2-Inch x 8-Inch construction and Grille Dimension: 13-Inch by 14-Inch