RYOBI 21 in. Replacement Blade is the best solution for replacing your RYOBI 40-Volt 21 in. Mower's damaged or dull blade. This blade is optimized for cordless mowers, improving cutting efficiency and increasing run time. Buy with confidence knowing that this OEM part will work with your RYOBI 21 in. 40-Volt Brushless Mower. Replacement part for: RY40LM10-Y and RY401130.