Why is Denso's air-conditioning filter element OEM?

Denso's air-conditioning filter is made by Kedebao, because Denso's air-conditioning filter uses the patented technology invented by Kedebao. According to the official website of People's Republic of China (PRC) and the China Patent Office, the filter element of Denso air conditioner was invented and produced by Kedebao Company, and applied for a technical patent on April 23rd, 20021year, and the patent protection time was 10. Other companies use patent production licenses.