The STIHL 42066420103 Worm Gear is a genuine OEM replacement part designed for optimal performance in STIHL BR and SR series backpack blowers and mist blowers. This critical component ensures efficient power transmission within the machine's gearbox, contributing to the smooth and effective operation of your equipment. Manufactured to STIHL's rigorous quality standards, it provides durability and precise fitment for models including BR 500, BR 550, BR 600, BR 700, BR 700 X, BR 800 C-E, BR 800 X, SR 430, and SR 450.