The John Deere Mulch Kit BM20827 comes with a set of mulching blades the two deck inserts and the fixings required to install it into your Mower Deck. This kit is used on the 54-Inch Convertible (54C), 54-Inch Side Discharge (54D) and the 54-Inch Edge Extra (54X) mower decks. The advantages of using a mulching kit over a collection system is that the grass clippings feed back into your lawn giving you a free natural fertilizer and you don't have to worry about disposal of grass clipping if you are using a collector.