Product details:

Gravity Ventilator, Blade Dia. 10 In., Base Size - Roof Ventilators 19 In. x 19 In., Style - Roof Ventilators Low Profile, CFM/Throat Velocity @ 0.050-In. SP Gravity Relief 370/650, CFM/Throat Velocity @ 0.100-In. SP Gravity Intake 442/775, CFM/Throat Velocity @ 0.100-In. SP Gravity Relief 524/919, CFM/Throat Velocity @ 0.125-In. SP Gravity Intake 494/866, CFM/Throat Velocity @ 0.125-In. SP Gravity Relief 586/1027