Surround Air XJ-3100SF Spare Hepa and Carbon Filter for Intelli-Pro 3-Air Purifier HEPA filter removes 99.97% of particles down to 0.3 microns in size, almost 300 times smaller than the width of a human hair Activated carbon air filters trap odors and chemicals in highly absorbent granules (or pores), which look like a hard scrub brush Lasts 1 -2 years Both filters combined into one for one low price Dimensions - 14.5" X 13"