Carbon Block CTO Water Filter Cartridges for Ro Reverse Osmosis System, 3 Pack Keeps water fresh by reducing and removing iron, manganese, chlorine, hydrogen sulfide, herbicides, pesticides, and other industrial chemicals Fits into any industry standard 10-inch housing This filter is ideal for a standard Reverse Osmosis Water Filtration Unit or any type of Water Filtration Unit with a 10 inch housing This filter is wrapped and sealed and meets NSF (National Science Foundation) Standards and Regulations Dimensions: 9.875 inches x 2.5 inches (25.7 cm x 6.35 cm)