Purity Pro PF03 Replacement Filter for GE MWF, Smart Water MWFP Made in Korea from NSF certified facility and out facility is regularly inspected by NSF 850 gallon capacity in average household environment NSF certified for removal of CTO (chlorine, taste and odor) 0.5 micron rating (nominal rating is 0.3 micron) Compressed carbon block compared to extrusion block of competitors