(NSI by Zeptometrix) QC all of your solids analyses with our ready-to-use, NIST traceable solids standards. Stable and remarkably easy to use, simply shake well and pour an appropriate aliquot. No pipeting, no dilutions minimize error. Packaged in an economical 4x1 liter case yielding up to nearly 250 QC analyses for the high level concentrations. Certifi cate includes true values, acceptance limits and NIST traceability information.