The P8 is designed for use with the Broan Elite RMIP series 850 CFM, 10.5 Sone (vertical discharge) or 900 CFM, 10.0 Sone (horizontal discharge) performance - HVI Certified Rough-in kits are included to make the installation clean and simple All our blowers are designed for quiet operation using the finest motors and balance wheels Internal Blower for RMIP series, 850 CFM, 3-1/4-Inch by 14-Inch duct size at discharge, 120-volt/60 Hz