Oregon 69-197 Gatorline Heavy-Duty Professional Magnum .130-Inch-by-50-Foot Coil of Round String Trimmer Line Outer layer prevents welding User friendly donut-fewer tangles High strength inner core resists breaking .130-inch diameter 50-foot donut High resistance to abrasion and breakage. Flexible core provides outstanding durability. Less engine drag, vibration, and noise. Engineered to resist welding up to 498 F. Outer layer prevents welding. User friendly donut  fewer tangles. High strength inner core resists breaking. Long-life, excellent strength. Fits all standard trimmer heads. User-friendly donut, limits tangles. Fits all standard trimmer heads. Effective in all cutting conditions.