Propeller, Replacement, Propeller Dia. (In.) 20 in, Bore Dia. (In.) 1/2 in, Number of Blades 4, Pitch (Deg.) 24 Degrees , Blade Material Spark Cast Aluminum, Keyway (In.) -, Number of Set Screws 2, Rotation CW Facing Discharge, Required Motor HP 1/2, Required HP @ Higher RPM -, RPM Low -, RPM High -, Max. RPM 1725, CFM @ 0.000-In. SP 4580, CFM @ 0.125-In. SP 3940, CFM @ 0.250-In. SP 3360, CFM @ 0.375-In. SP 2,840 cfm, CFM @ 0.500-In. SP 2,325 cfm, Blade Height (In.) -