Propeller, Replacement, Propeller Dia. (In.) 20 in, Bore Dia. (In.) 1/2 in, Number of Blades 3, Pitch (Deg.) 23 Degrees , Blade Material Aluminum, Keyway (In.) -, Rotation CW Facing Discharge, Required Motor HP -, Required HP @ Higher RPM 1/4 hp, Required HP @ Lower RPM 1/15 hp, RPM Low 1,050 RPM, RPM High 1,500 RPM, Max. RPM 1725, CFM @ 0.000-In. SP 3697/2588, CFM @ 0.125-In. SP 3479/2246, CFM @ 0.250-In. SP 3221/1643, CFM @ 0.375-In. SP -, CFM @ 0.500-In. SP -, Blade Height (In.) 3 7/8 in