Direct Replacement Part: This replaces part numbers 4009 710 2106 and C3-2, ensuring compatibility with Stihl FSA 57 and FSE 52 models from 2020 onwards. Designed for seamless integration, this head restores performance. Compatibility and Performance: Specifically designed for Stihl FSA 57 (2020 On) and FSE 52 (2020 On) trimmers, this C3-2 features a bump and feed mechanism that automatically feeds the nylon line with a simple tap action. Advanced Feeding Mechanism: The C3-2 operates with a bump & feed system where the nylon line is fed automatically by tap action. This feature enhances ease of use and efficiency, making your trimming tasks quicker and smoother. Versatile Line Options: Compatible with 2.0mm / .080inch diameter line, this double line is ideal for both trimming and mowing tasks. It offers flexibility in line choice, adapting to various grass types and conditions. Color: Black & White Material: Plastic Package Contents: 1 x C3-2 (The color of the rope is random, no specified color is accepted) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to be slightly different from the real thing. The measurement allowed error is +/- 1-3cm.