This heavier duty (brand dependent) unit is great for trimming and edging. Some models have the option of attaching a brush blade in place of the trimmer-line head. This circular-saw-like blade can cut through large grasses, vines and brush like a knife. Certain blades can actually cut down scrub trees up to 4" diameter. Use only blade kits specifically designed for the model and never, ever, attach metal cables or chains to the trimmer head. These will break-off in pieces and embed themselves deeply in whatever they strike!