Specifications 90 Series Grade PE Filter Element 1 Micron 5 PPM Oil Content Particulate (After-Filter) Filters A particulate filter, also known as an after-filter, is usually located just after the desiccant air dryer to remove harmful liquid oil, water condensate, pipe scale, dirt and rust from your compressed air system. This helps prevents contaminants & corrosive damage to compressed air equipment and finished products. If the particulate filter gets soiled more frequently than what is typical for your environment, it may be time to replace the desiccant. Our Particulate Filter Replacements come with a manufacture's warranty that matches or exceeds the original OEM warranty. Original equipment manufacturer (OEM) names are the trademarks of each manufacturer. On products marked "replacement," OEM names and part numbers are for reference only.