The permanent FN1 filter compresses fluids, trapping foreign particles between its grooved plates and wave washers. When the element is decompressed, the foreign matter is washed away for collection. Recompression continues normally. Available in filter or step type, it is made of stainless steel. Also, the FN1 is compatible with many liquids, including water, and water-soluble and oil-based coolants, petroleum and ammonia hydroxide, sodium hydroxide, and alkalis. For more information, go to http://rbi.ims.ca/3851-529.