NSF Certified Compressed Carbon Block Filter, CTO Purity MAX,10", 1 Micron, WWC101 Chlorine Taste and Odor removal (NSF 42 Certified) 9 3/4 x 2 1/2 inches (9.8 X 2.5 inches) Particle retention size of 1 micron 10,000 Gallon capacity Carbon block filter for a water filtration system