Fast. Quiet. Simply Smart. Our signature performance is now even better, delivering more cleaning power. Blue Pure 211i Max features enhanced performance with our proprietary HEPASilent technology, which combines electrostatic and mechanical filtration to capture at least 99.97% of airborne particles down to 0.1 micron in size. Even the tiniest particles, such as viruses and bacteria, are captured, along with larger household particles such as dust, pollen, pet dander and smoke.