The CF3 Pro Trimmer Line. This rugged line is formed using 3-component, tri-extrusion technology. Its high-quality polyamide components ensure strong durability with excellent cutting performance. Best of all, it is compatible with all STIHL nylon line trimmer heads, making the CF3 Pro at home on any landscape trailer or in any garage. Whether you’re a homeowner with challenging terrain or a professional landscaper requiring more wear and tear out of your line, the CF3 Pro is a line you can stand behind.