For lawn tors and zero-turn riding mowers using part #942-0616/ 742-0616, 942-04308/ 742-04308, 942-04312/ 742-04312 6 point star center hole pattern Kit includes 2 mulching blades, 1 molded plug and mounting hardware Blades should be inspected and sharpened or replaced every season. Sharp-edged blades cut grass cleanly and make their way through grass more efficiently, reducing overall mowing time and effort and creating a healthier-looking lawn.Mulching blades create biodegradable clippings to help fertilize lawn and return nutrients to the soil.