Package includes:</br> 3 HEPA Filters and 12 Activated Carbon Pre-Filters</br></br> An ideal true HEPA air purifier filters replacement professionally designed for your units. We suggest changing the HEPA filter after 8-12 months and the activated carbon pre-filter every 2-3 months or as needed.</br></br> This is not a guardian OEM product. Any use of the brand names or model designation for this product is made solely for purposes of demonstrating compatibility.