The STIHL 4006 710 4003 is a genuine OEM cap (spool retainer) for the AutoCut C 6-2 mowing head. It securely retains the spool inside the trimmer head while protecting it from dirt, dust and impact damage. Manufactured from durable, impact-resistant polymer, this cap is designed as a direct replacement for worn or damaged originals, ensuring smooth bump-feed operation and reliable line advancement.