US operator manual · two listed head families

What size trimmer line does the STIHL FSA 57 use?

The cited US FSA 57 manual lists round or round-quiet nylon line in 1.6 mm (0.065 in) or 2.0 mm (0.080 in) with the approved AutoCut C 3-2 and PolyCut 3-2 heads.

Do not use metal or metal-reinforced line. The manual explicitly prohibits it. Remove the battery and follow the manual’s procedure before adjusting or loading line.

Head-specific source record

Head in manual	Diameter	Material / profile
AutoCut C 3-2	1.6 mm (0.065 in) or 2.0 mm (0.080 in)	Round or round-quiet nylon
PolyCut 3-2	1.6 mm (0.065 in) or 2.0 mm (0.080 in)	Round or round-quiet nylon

Confirm the head before using the lookup

Look at the head’s name and model, then compare with the diagram/parts description in the operator manual. If you have a different head, use its specific instructions; the FSA 57 manual’s line table does not automatically cover every attachment.

Sources and version limits

The record is transcribed from STIHL’s US instruction manual, version 0458-806-8621-B, checked October 19, 2026. Another manual revision or serial range may differ. Use the manual associated with your exact tool/market when it differs.

Find STIHL FSA 57 owners instruction manual on official US manual search ↗ · STIHL FSA 57 US product/cutting-head information ↗

Independent reference prototype. Consult official STIHL documentation for complete operation and safety instructions.