DC, DZ crude and sub-efficient bag filter Adopting non-woven fabrics as filter and cold plate spray as the framework, using them as one and two filters, the product has the advantage of large capacity, low resistance and easy cleaning. According to the differences of environment and materials, the filter efficiency level is divided into F5, F6, F7, F8. Air Filter is a kind of air filtration devices. It is generally used for cleaning dust in a clean shop, clean rooms, laboratories and clean rooms, or for protecting electro-mechanical communication equipment from dust. The Air Filter models include the primary efficiency air filter, medium efficiency air filter, high efficiency air filter and sub-efficient filter and others with different standards and performance.