<b>Particle and Activated Carbon Replacement Filter</b> for Blue Pure 211+ <br> <br> Using a 360-degree air intake and up to 4 times the filter surface area than competing replacement filters, the Particle and Activated Carbon Filter lasts longer, on average from 6 months to a year. <br> <br> The click-and-change filter is easily removed and replaced, and can be put into recycling at the end of its service life.