23" Extreme blade for Cub Cadet Tractors with 42" decks, 2010 and after. Also fits RZT's, 2011 and after. Star center. Extreme blades feature more cutting surface than standard blades. They create finer mulch and less thatch. When bagging, they lift up to 50% more clippings off of the lawn and when using side discharge, they leave smaller clippings on the lawn.