This cab filter captures airborne dust and pollen before the air enters the operator station. It sits in the housing on the roof or rear wall of the cab, filtering the intake air that the HVAC system then conditions and distributes. A clogged filter reduces airflow across the evaporator and heater core, causing poor defogging and insufficient cabin pressurization. The filter media is pleated to maximize surface area within the given housing dimensions. On replacement, ensure the sealing gasket seats evenly against the housing flange to prevent unfiltered bypass air.