Ensure your under sink PQC1FS or PQC3RO water filtration systems continue to produce cleaner, better-tasting drinking water with the Vitapur VQCCRBKIT filter replacements. This kit includes two quick-connect 5 micron carbon block filters that are NSF certified to reduce chlorine and particulates, such as sand, rust and dirt. The quick-connect design makes replacing the filters simple and easy. For optimal system performance, replace the filters every six months.