Propeller, Replacement, Propeller Dia. (In.) 20 in, Bore Dia. (In.) 1/2 in, Number of Blades 3, Pitch (Deg.) 20 Degrees , Blade Material Aluminum, Keyway (In.) -, Rotation CW Facing Discharge, Required Motor HP -, Required HP @ Higher RPM 1/3 hp, Required HP @ Lower RPM 1/10 hp, RPM Low 1,140 RPM, RPM High 1,725 RPM, Max. RPM 1725, CFM @ 0.000-In. SP 3766/2489, CFM @ 0.125-In. SP 3587/2183, CFM @ 0.250-In. SP 3375/1574, CFM @ 0.375-In. SP -, CFM @ 0.500-In. SP -, Blade Height (In.) 3 7/16 in