21560070 SRM Trimmer Head

Key Features

• Reliable Semi-Automatic Feed: The classic Echomatic "bump" system provides instant line advancement with a simple tap on the ground, ensuring you never have to stop mid-job to manually pull line.
• High-Impact Structural Polymer: Manufactured from a specialized glass-reinforced nylon composite to resist cracking and shattering during high-velocity impacts with curbs and fence posts.
• Optimized Dual-Line Performance: Features an internal spool design that feeds two lines simultaneously, providing a balanced, level cut that is ideal for both manicured lawns and heavy weed clearing.
• Pre-Wound with 0.095" Line: Comes factory-loaded with professional-grade 0.095-inch diameter line, offering the perfect balance of cutting power and durability for standard garden maintenance.
• Centrifugal Balance Engineering: Designed to minimize motor vibration and shaft wobble, which reduces operator hand fatigue and prevents premature wear on the trimmer's gear head bearings.

Replaces / Cross-Reference Part Numbers

• 21560070
• 21560050
• 200095200
• 215600501
• 21560031

Compatibility & Fitment

This Echomatic head is the traditional standard replacement for Echo’s straight-shaft SRM trimmer series. Key compatible models include:

• Echo SRM Entry Series: SRM-210, SRM-225, SRM-225i, SRM-2100, SRM-2110.
• Echo Professional Series: SRM-230, SRM-231, SRM-235, SRM-250, SRM-265, SRM-266.
• Echo PAS Attachments: Compatible with most straight-shaft Pro Attachment Series trimmer heads.
• Technical Fitment: Designed for models utilizing the M10 x 1.25 LHF (Left Hand Female) arbor thread.

When to Replace

• Worn-Through Bump Surface: The bottom of the head has ground down from pavement contact to the point where the internal spool is exposed or the line no longer advances correctly.
• Cracked Outer Shell: Visible stress fractures or missing chunks of the black housing, which can cause the head to become dangerously unbalanced at high RPMs.
• Internal Spool Jamming: The plastic "locking teeth" inside the head have rounded off, causing the head to dump all the line at once during use.
• Eyelet Failure: The metal line exits (eyelets) have fallen out or are deeply grooved, causing the trimmer line to snap off inside the head repeatedly.
• Excessive Vibration: The head has become structurally unsound or unevenly worn, putting undue stress on the gear head and drive shaft.

Installation Tips

• Left-Hand Threads: Remember, this head is Left-Hand Threaded. To tighten it onto the trimmer, you must turn the head Counter-Clockwise.
• Lock the Gear Head: Insert a small hex key or the factory locking pin into the gear head hole to hold the shaft stationary while you spin the old head off and the new one on.
• Spool Direction: When reloading line, follow the arrows molded into the internal spool. Winding the line in the wrong direction will prevent the semi-automatic feed from working.
• Soak Your Line: To extend the life of your trimmer line, soak the spool in water for 24 hours before use. This keeps the nylon flexible and resistant to snapping at the eyelet.
• Clean the Internal Spring: Every time you reload the line, shake out any dirt or dried grass trapped around the internal spring to ensure the "tap" action stays smooth and responsive.