OEM set of 3 - 2500540 blades
540 models (19" blade) 15/16" bore
OEM set of 3 - 2500541 blades
561 / 610 models (21" blade) 15/16" bore
OEM set of 3 - 2500543 blades
720 models (24-1/2" blade) 15/16" bore