More durable. More flexible. Less hassle. Aero-Flex Line Blades are aerodynamically designed and engineered to perform best at low speeds. Flexible yet durable, our blades last longer than traditional plastic string and can be easily replaced without the hassle of spools, springs, or rewinding, and do not break on contact with obstacles. Plus, with four powerful blades attached at any given time, Aero-Flex Line Blades cut vegetation more frequently during each revolution for a more uniform landscape. With a more rigid design and greater mass than traditional plastic string, Aero-Flex Line Blades are capable of mulching, trenching, and mowing in addition to edging. Their neon coloring gives users additional visibility for their cutting radius so they can ensure they are only cutting what they want, where they want. Package is a mix of orange and yellow blades. Use two orange and two yellow for both clockwise or counterclockwise rotating trimmers.