Custom RO 15 Filter Pack Includes all filters for RO systerms that requier a .5 micron CTO/VOC carbon pre-filter, two 5 micron carbon block post filters.Also includes replacement o-rings for canisters. Meets manufactures requierments for replacment filters. Keep your RO system at peak performance with quality filters. Includes the service manual "How to Service Your Reverse Osmosis System" by Dionicio Porras. ROFCTK, Filter change tool kit available separately. Service your RO like a pro!