【Specifications】 Replacement for Stihl Autocut C3-2 trimmer head, with pre-installed trimmer line (supports up to 2 mm diameter). 【Suitable Models】 Compatible with Stihl FSA 57 trimmer (from 2020, serial number above 522544906), FSE 52 (from 2020). 【Pre-installed Line】 The C3-2 trimmer head is pre-installed with trimmer line. And the trimmer line can be replaced from the outside without disassembly. 【Simple Operation】 When mowing, the trimmer line can be adjusted automatically by pressing the line head, allowing you to mow quickly and efficiently. 【Durable Material】 Practical two-line spool for FSA57 and FSE52, durable enough for lawn environments. Ideal for garden mowing.