Genuine OEM BMW crankcase breather hose, part number 11157843151. This hose is a critical component of the crankcase ventilation system, designed to safely route blow-by gases from the crankcase back into the intake system for combustion. It is constructed from oil-resistant materials to withstand high temperatures and chemical exposure. As a genuine OEM part, it features the correct pre-formed geometry and integrated quick-connect fittings to ensure a leak-free seal and proper vacuum regulation within the engine.