This part is a replacement single mulching blade that is used on lawnmowers and lawn tractors. This blade is used for mulching lawn clippings.A new mulching blade may be needed if, upon visual inspection, the part is bent, cracked, broken, or damaged in any way. If the grass is not being effectively mulched and the blade is dull, it is possible that a new mulching blade may be needed. The blade can become damaged or broken if it comes into impact with another object, such as a large rock. A general rule is that mower blades should be replaced every two years. This part is a genuine Midwest Engine part and is an OEM part sourced directly from the manufacturer and it is sold individually. This specific single mulching blade is used on lawnmowers and lawn tractors that are manufactured by Murray. The length of this blade is 21-3/16” and the width is 2.25”. There are two blades per lawnmower or lawn tractor.