Identify the cutting head fitted to your trimmer.

A tool model can support multiple attachments, and a replacement head may have its own line limits. Record both labels before treating a model lookup as relevant.

Do not remove guards or open a head while the tool can start. Switch it off, remove the battery or disconnect power as directed by the exact manual, and follow its inspection steps.

Check these clues in order

Read the tool label. Copy the complete model and suffix from the equipment, not the battery, charger, or retailer title.
Look for the head name or part number. Use only the inspection method described in the manual. Some heads carry markings; others are identified in the tool’s parts diagram.
Match the head to the parts diagram. Check that the pictured assembly and part number match the installed attachment and model revision.
Find the head’s own line instructions. Confirm diameter, shape, loading method, and any material restrictions. The largest diameter accepted by a generic spool is not automatically approved for your tool.

Why both identifiers matter

A line-size result is only applicable to the model, market, and head named by its source. If the head differs, the result is unresolved even when the tool model matches. Aftermarket heads can carry separate instructions; check the head maker’s documentation and the tool manufacturer’s safety restrictions.

If the label is missing

Use the exact tool manual and manufacturer parts support to identify the intended head. Do not infer the head from color, shape, or a photo match alone. Keep the lookup blank and contact the manufacturer if the tool and attachment references disagree.

Check a documented model ↗Compare line labels ↗Troubleshoot breakage ↗

Method note: this checklist reflects the app’s source rule: apply a published limit only to the exact model/head combination named by its manufacturer source. Review the product’s applicable manual before use.