BV Ultra-Quiet 90 CFM, 0.8 Sone Bathroom Ventilation and Exhaust Bath Fan Super quiet performance. Silent-Clever Technology with only 0.8 sone; Mount Type : Surface Mount Mounting opening: 9.25" x 9.0". Height: 7.5" Stainless steel 4" duct collar HVI 2100-certified and UL Approved. Quality & performance assurance. Ventilating for bathroom space up to 90 sq-ft One-year limited product warranty with technical support service included Note-be careful to cut the hole exactly because if it is too big, the grille will not hide it. Ceiling opening is 9.4 long x 9.4 wide x 8.23 deep in inches. Housing dimension is 9 x 9 x 7.6 in inches