0000 140 4407 – STIHL HD2 Air Filter (Genuine OEM Part)0000 140 4407 STIHL HD2 Air Filter (Genuine OEM Part) The STIHL 0000 140 4407 is a genuine HD2 Air Filter, engineered to provide superior filtration and protection for STIHL engines operating in demanding environments. Featuring STIHLs innovative HD2 design, this filter uses a special polyethylene material that offers up to 70% finer filtration than traditional fleece or felt filters. This high performance air filter blocks fine dust, dirt, and