Check the listing for details. Two Big Blue 20" x 4.5" CTO Carbon Block Filter (5 micron). Color: Blue, Condition: New. Listed at 49.00 USD. Two 20" x 4.5" Jumbo CTO Activated Carbon Filter (5 micron)for Big Blue Whole House Water Filter System Note: This item is on the way to our inventory. It will take us up to 30 days to fulfill your order. If you need the product sooner than that, please consider our 1 micron filters (eBay item #322687256158), which are available right now. Thank you. Specifications:Individually wrapped in films for freshness. Fits all Big Blue 20" x 4.5" Water Filter Housings. CTO filter adsorbs chlorine, halide, organic contaminants, odors, and other impurities that contribute to bad taste and odor.Flow rate: 8~10 GPM;Filter life: 20,000 gallons or every 8-12 month;Dimensions: Length = 20", O.D. = 4.5", I.D. = 1 1/8"Note: Active charcoal carbon filters are most effective at removing chlorine, sediment, volatile organic compounds (VOCs), taste and odor from water. They are not effective at removing minerals, salts, and dissolved inorganic compounds, which are main sources of TDS (Total Dissolved Solid) reading. That means you will not see a significant drop on TDS readings by any carbon filters. Typical particle sizes that can be removed by carbon filters range from 0.5 to 50 micrometres. The efficiency of a carbon filter is also based upon the flow rate regulation. When the water is allowed to flow through the filter at a slower rate, the contaminants are exposed to the filter media for a longer amount of time. The package includes: 2 pieces of 5 Micron 20" x 4.5" Activated Carbon Block (CTO) Filter On Nov-10-12 at 21:00:50 PST, seller added the following information: Add a map to your own listings. FREE Trial !