Cassette filters are filtering units generally used in ventilation and air conditioning systems. These filters have a cassette-like structure, usually square or rectangular, and are designed to filter air flow. Cassette filters are used to retain airborne particles and pollutants. They can often have various filtration levels and efficiency classes. These filters are generally used to improve indoor air quality by using them in air inlets and outlets, air ducts and ventilation units. Maintenance and replacement of cassette filters is important to ensure proper functioning of HVAC (Heating, Ventilation and Air Conditioning) systems and maintenance of indoor air quality. Cleaning or replacing filters regularly prevents airflow from being blocked and filtering efficiency reduced. Cassette filters often have special designs that optimize airflow and can be easily installed. These filters are often used in industrial facilities, office buildings, shopping malls and other commercial and industrial applications.