HEPA filters are the highest standard for air filtration. In the workshop and on the job site, airborne dust from power tools can have serious consequences to health. Keep work areas clean and healthy with this Festool HEPA dust extractor filter element. It's designed to be used with the Festool CT 22 and CT 33 HEPA dust extractors. HEPA filter (Festool 493334) captures 99.99 percent of particulate matter down to .3 microns Traps small particles while maintaining air flow; won't clog or cake Package includes 2 HEPA filter elements for the CT 22 and CT 33