Aftermarket mulching blade fits Gravely ProMaster 300 & Gravely Pro 40. Replaces Ariens/Gravely 52929, 052929, 886690 and 08866900. 15-6213. All blades are sold individually. Order quantity of (3) blades for 60" cut. Be sure to match the part number from the owners manual for the part you are replacing with the OEM number(s) listed.