This filter is a special type. At present, it has only 1.2-inch, 1.5-inch and 2-inch models. The filter screen is made of stainless steel, and the connecting parts with the fan are plastic. The external thread can be directly connected to the fan. The double-layer filter screen can effectively prevent large sundries from being sucked into the fan and causing impeller damage. It can not filter dust and can be washed with water