More responsive operation: Older keys are susceptible to wear and tear, and problems such as unresponsiveness and key failures can occur. After replacing the controller, the tactile feedback is clear, and the keys respond quickly, avoiding the trouble of repeated pressing, and the daily control is more worry-free. Safety guarantee: The aging of the old controller circuit can easily lead to poor contact, which may cause abnormal heating or short circuit, reduce the risk of circuit failure after replacing the controller, and ensure the safety of household electricity. Precise temperature control: The chip accurately transmits instructions to avoid frequent start and stop of the compressor caused by temperature error. Reduce invalid run time. Extend the life of the air conditioner: The stable current output can reduce the working load of the circuit board and compressor, reduce the aging of components caused by control disorders, maintain the air conditioning performance for a long time, and avoid frequent maintenance or early scrapping. Compatible for Mitsubishi ， PAR-21MAA