MaxPower's 561812XB includes (3) 3-N-1 commercial style mulching blades for many 48 in. John Deere mowers. These blades replace OEM #'s GX21784, GX21786 and GY20852. Each blade measures 17 in. L and 2-3/4 in. W and with a 7 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. Check your owner's manual to verify that the OEM number of the blade being replaced matches one of the OEM numbers provided for this item. Maxpower blades are manufactured to meet or exceed OEM specifications. Proudly made in the USA.