Stainless steel perforated, woven kitchen sink strainer Kitchen sink strainer is a type of stainless steel perforated or woven colander or strainer used in kitchen to keep food particles and other debris from going down the drain, creating blockage. Advantage: As shown in the picture, the sink strainer is designed as double filtering in order that all waste can be fully filtered. Usually, the first strainer is designed like a wheel to let the water to pass smoothly and stop big waste on the surface. The second strainer is like a container with many holes on it, with which waste things can be concentrated here and prevent them from blocking the sewer.