Vio® Air Purifier Replacement Filter is designed for use in the Vio® Personal Air Purifier. The Vio® Air Purifier utilizes HEPA H-13 filtration technology to remove 99% of airborne particles such as dander, pollen, smoke and dust to provide clean air. Timing of replacement depends on the usage and location (i.e.: quality of the air, number of hours operating, size of space, etc.)