This listing is for 6 filters. It is just a few pennies over $5 per filter. Reduces sand, silt, scale, and rust particles in residential and municipal drinking water and industrial fluid applications Nominal filtration rating of 5 microns Polypropylene cord precisely wound on a rigid core for high dirt-loading capacity Initial pressure drop of less than 2.5 psi at a flow rate of 10 gpm Temperature range of 40 to 145 degrees F (4.4 to 62.8 degrees C). This Pentek WP-5 string-wound polypropylene filter cartridge reduces fine sediment, rust, and scale particles for municipal drinking water and industrial fluid applications. It has a nominal filtration rating of 5 microns at an efficiency of 85%. The filter is made of polypropylene fiber cord that is wound in a precise pattern on a rigid polypropylene core for greater surface area, providing a higher dirt-loading capacity than standard wound cartridges. It has an initial pressure drop of less than 2.5 pounds per square inch (psi) at a maximum flow rate of 10 gallons per minute (gpm), and operates over a temperature range of 40 to 145 degrees F (4.4 to 62.8 degrees C). This string-wound filter cartridge is for use in various applications, including drinking water purification, irrigation, and industrial processes, among others. Specifications Nominal filtration rating 5 microns Initial pressure drop at 10 gpm 2.5 psi Operating temperature range 40 to 145 degrees F (4.4 to 62.8 degrees C) Maximum dimensions (H x W) 9-7/8 x 2-1/4 inches (251 x 60 mm) The nominal filtration rating is for a particle removal efficiency of 85%. H is height, the vertical distance from lowest to highest point; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back. Water filters remove undesirable particles, chemicals, and microorganisms from water by means of a semipermeable barrier, adsorption, or biological processes. They are made of densely packed synthetic or natural fibers that trap suspended particles, materials that block microbes or adsorb unwanted chemicals, or substances that cause a chemical change, such as acid neutralization. For most residential, commercial, and industrial applications, water filters are manufactured in the form of replaceable cartridges that fit inside permanent housings. Filtration systems typically consist of a series of two or more types of filters, each designed to remove different contaminants. The performance of filters is measured by the minimum particle size that is blocked, the percentage of particles or microorganisms that are removed, the downstream concentration of unwanted chemicals, the maximum flow rate, and the amount of water that can be filtered before the filter must be replaced. Water filters are used in a wide range of applications, including drinking water purification, swimming pools, industrial processes, and irrigation, among others. Pentair manufactures industrial, commercial, and residential water filtration components and systems. The company, founded in 1966 and headquartered in Minneapolis, MN, meets International Organization for Standardization (ISO) standards 9001 and 14001 for quality assurance.