The CF3 Pro trimmer line. This rugged line is formed using three component, tri-extrusion technology. It's high-quality polyamide components ensure strong durability with excellent cutting performance. Excellent 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.