This unique lawnmower blade adapts to Most 17-Inch to 22-Inch gas and electric , push and riding lawnmowers. It uses a trim to fit technology so very easy to have the blade fit most lawnmowers. The blade sharpens as it cuts so it will give you a good cut for a long time to come and no blade sharpening to worry about. It is also very safe in that it is designed to prevent cutting through leather shoes. It is also non-sparking which eliminates fire danger. Aerospace-Grade Polymer. It has a slow wear composition for long blade life.