Complement your mower with the RYOBI 21” Self-Sharpening Lawn Mower Blade. With 2X longer blade life than a standard blade, maintain maximum performance without having to change your blade as frequently. It self-sharpens by exposing an additional sharp surface as the blade's base layer wears away over time. When lawn mower blades are regularly maintained, the mower’s cutting efficiency and runtime increases for an overall better mowing experience. Feel confident in your cut as this blade is made with hardened steel and features a laser treated edge making it dependable and durable. For best results, replace your self-sharpening mower blade after two years of use. Complement your tool collection with RYOBI Accessories. The RYOBI 21” Self-Sharpening Lawn Mower Blade is optimized for RYOBI 21” Lawn Mowers, RY401140/RY401014, RY40HPLM01, RY40HPLM05, also fits RY401150/RY401015, RY401210/RY401021, RY40HPLM02, and includes 21” Mower Blade and Operator's Manual.