Surround Air S5000CF Carbon Filter - About Surround Air A division of Indoor Purification Systems, Inc., Surround Air, has been providing breathability and purification to the environments you occupy since 1998. They're proud to provide air purifiers and humidifiers of all sizes and price ranges that incorporate the latest and most reliable technologies and materials. Advanced true HEPA filters, germ-killing technologies, odor-eliminating carbon filters, built-in ionization, air sanitization, photocatalytic filters, and many more advanced techniques go into Surround Air products, so that only clean air comes out. They also make and distribute low-cost and high efficiency replacement filters and parts for all their equipment, so It's easy to keep it green and clean. Invite Surround Air into your home or business and breathe easy. Easy-load design. Carbon atoms create a highly absorbent material. Carbon air filter for trapping chemicals, gasses, odors. Negative ions to improve efficiency of filter units. Replacement filters ensure up to 6 to 12 months of use.