Propeller Replacement Propeller Dia (In.) 12 in Bore Dia (In.) 1/2 in Number of Blades 3 Pitch (Deg.) 33 Degrees Blade Material Aluminum Keyway (In.) - Rotation CW Facing Discharge Required Motor HP - Required HP @ Higher RPM 1/20 hp Required HP @ Lower RPM 1/60 hp RPM Low 1 050 RPM RPM High 1 550 RPM Max RPM 1725 CFM @ 0.000-In. SP 1087/737 CFM @ 0.125-In. SP 945/536 CFM @ 0.250-In. SP 809/325 CFM @ 0.375-In. SP - CFM @ 0.500-In. SP - Blade Height (In.) 2 29/32 in