This listing is for three filters.The Pentek GS-10RO-B Inline Filter Cartridge Replacement is a 10" in-line filter which uses coconut shell granular activated carbon (GAC) for cleaner, better tasting water. It can be utilized in numerous applications such as reverse osmosis systems, food service, water coolers, refrigerators, ice makers, vending equipment, under sink filter systems, and more to reduce the bad taste and odor of chlorine as well as particulate matter such as sediment, dirt, rust, sand, silt, and so on.The Pentek GS10ROB In-line Filter has 1/4" Female Pipe Thread connections (1/4" FPT) - it is compatible for use in all inline filter applications which use that specific connection fitting.Pentek GS-10RO-B Coconut Shell GAC In-Line Filter Replacement Specifications:Temp. Range: 40-100 FMax. Pressure: 125 PSIMicron Rating: 5 micronsDimensions: 10" length x 2" diameterConnection: 1/4" Female Pipe Threads (1/4" FPT)Flow Rate: About 1/2-1 gallon per minute (0.5 GPM/1 GPM)Filter Media: Coconut shell granular activated carbon (GAC)Filter Life: Approx. 6-12 months depending on local water quality and frequency of useThis Pentek in-line filter needs to be replaced about every 6-12 months or when a reduction in flow occurs. The Pentek GS-10RO-B in line filter is also known by Pentek part number 255521-43 / 25552143.