Propeller Replacement Propeller Dia (In.) 12 in Bore Dia (In.) 3/8 in Number of Blades 3 Pitch (Deg.) 28 Degrees Blade Material Aluminum Keyway (In.) - Rotation CW Facing Discharge Required Motor HP - Required HP @ Higher RPM 1/25 hp Required HP @ Lower RPM 1/70 hp RPM Low 1 050 RPM RPM High 1 550 RPM Max RPM 1725 CFM @ 0.000-In. SP 928/629 CFM @ 0.125-In. SP 799/437 CFM @ 0.250-In. SP 664/174 CFM @ 0.375-In. SP - CFM @ 0.500-In. SP - Blade Height (In.) 2 9/16 in