We are proud to introduce the first dry performance air filter, the AEM DRYFLOW Synthetic air filter. The DRYFLOW is independently tested to have a filter efficiency of 99.4% and it filters down to one micron of particulate. It NEVER needs oiling, which eliminates vehicle warranty issues and reduces service time. Its also incredibly durable. Please refer to the independent test results on the product feature page, and click on the DRYFLOW air filter in the product interactive for more information!