THIS IS A MATCHED SET WITH A 5" STEEL BLADE HUB FOR 2,3 OR 6 AIR-X TYPE BLADES
AND AN ADAPTER FOR A 1/2" SMOOTH OR

KEYED MOTOR SHAFT. THEY HAVE (2) 5/16" SET SCREWS  90 DEGREES APART 

LIKE THEY SHOULD BE. AND HAVE A WIDE FLANGE FOR STRENGTH AND RIGIDITY.