The sink stopper can be used as a filter or as a plug. When used as a filter, just align the drain and then rotate it 90 degrees and gently put it in. When used as a plug, it needs to be aligned with the drain port and Direct stuffed down. kitchen sink strainer and stopper combo basket replacement for standard 3-1/2 inch drain, stainless steel basket with plastic knob, rubber stopper bottom. The sink plug strainer fits most kitchen with standard 3-1/4 inch drains in the USA. Featured design The filter screen of the sink is specially designed with large holes around the small holes at the bottom, which not only maximizes the flow rate of water, but also achieves the purpose of filtering residues. There are vertical lines around the filter screen of the sink and the handle of the plug, which can increase friction, make it easy to remove, and facilitate cleaning.