Oregon 21-855 Gatorline Square String Trimmer Line .155-Inch Diameter 3-Pound Spool, Green

What It Is

This is a 3-pound spool of .155-inch diameter square trimmer line from Oregon, designed for heavy-duty weed trimming in commercial or tough residential conditions. The square shape and thicker gauge cut through thick grass, briars, and light brush more aggressively than round line.

Fitment & Compatibility

• Diameter: .155-inch is compatible with most gas and high-end electric trimmers that accept line up to .155-inch (check your trimmer head’s max line size—many standard heads top out at .130 or .150).
• Spool size: 3-pound spool is large; ensure your trimmer’s line feed mechanism can handle a spool this heavy (common on commercial trimmers, but some residential units may struggle with weight or spool dimensions).
• Brand fit: Not OEM for any specific brand—works as aftermarket replacement for trimmers that use .155-inch line, including EGO, Echo, Stihl, Husqvarna, and others. Always check your owner’s manual for approved line diameter.
• Measurements: Spool dimensions are approximately 8 inches diameter x 2.5 inches tall. Verify clearance in your trimmer head or storage area.

Key Things to Know

• Quality: Oregon Gatorline is known for durability and reduced fraying compared to budget lines. The square edges wear down to a rounded shape, maintaining cutting performance.
• Installation: Loading a 3-pound spool can be awkward—have a second person or a vise help hold the spool steady while threading. Follow your trimmer’s loading instructions carefully to avoid tangles.
• Common gotcha: This line is thicker than typical residential line. If your trimmer head has a small-diameter feed hole or a spring-loaded bump feed, it may jam. Test a short length before loading the full spool.
• Storage: The large spool can be heavy to store on a trimmer—consider using a line cutter or keeping the spool in a dry place to prevent brittleness.

Should You Buy It

Buy if you have a commercial or heavy-duty trimmer that accepts .155-inch line and you need to power through thick weeds or brush without frequent line changes. Skip if your trimmer is a lightweight electric model with a .130-inch max line size—the thicker line will cause feeding issues and may damage the head.