1 set of replacement filters with following : 4 x 20 Inch x 4.5 Inch Big Blue CTO Coconut Shell Carbon Block Water Filters Size 19 7/8 inch x 4.5 inch fits most 20 inch Big Blue housings 5 Micron nominal filter rating. Carbon block filters are extremely effective for removing chlorine taste and odors from your drinking water along with sediment removal. Filter Life: 26000 Gallons @ 7GPM. Operation Temperature: 40°F to 125°F Operation pressure 25 to 75 PSI maximum. Total 4 filters, each individually wrapped.