MaxPower's 331749XB includes 1 commercial mulching blade for many 22 in. cut Craftsman, Husqvarna and Poulan mowers. This blade replaces OEM #s 580244001, 580244002, 587199603 and measures 21-15/16 in. L x 2-1/2 in. W with a 5 point star center hole. Commercial mulching blades feature greater cutting surface for increased mulching performance, sharpened cutting teeth for a precision cut, and a centrifugal air lift design for uniform chopping distribution. To ensure proper fit, please verify the OEM # of the blade you are replacing matches the OEM # listed in this description. MaxPower blades are proudly manufactured in the USA to meet or exceed OEM specification.