Complement your mower solutions with the RYOBI 21” Lawn Mower Multi-Blade System Replacements. These CROSS-CUT™ Multi-Blades are optimized to provide superior cutting for the best bagging, mulching, and side discharge performance. 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 these blades are made with hardened steel, making them dependable and durable. For best results, replace your mower blades every year. Complement your tool collection with RYOBI Accessories. The RYOBI 21” Lawn Mower Multi-Blade System Replacements are optimized for RYOBI 21” Lawn Mowers RY401210/RY401021 & RY401220/RY401022, also fits RY401150/RY401015 & RY401200/RY401020, and includes 21” Mower Blades and Operator's Manual.