Replacement twin Under Sink water filter cartridges for twin undersink water filtration systems. These are universal filters and fit all makes and models of undersink water filter systems. 1 x USA made 1 micron pre-filter plus 2nd stage your choice of CRPB .45 micron Multipure cartridge or 0.5 Micron nominal MATRIKX® + Pb1 solid carbon block water filtersor CR1 Matrikx cartridge or 0.4 micron Multipure super block small bore water filter for the effective removal of heavy metals, chemicals, chlorine, foreign organic compounds, bacteria, giardia and cryptosporidium cysts, dirt, sediment and rust,  as well as other nasties present in our water supply. All USA made. Please choose filter options in shopping cart.