XS PROFESSIONAL: GUARANTEE AND ACCREDITATION PH and Conductivity measurements are all the more accurate the more reliable the solutions used for calibration. XS PROFESSIONAL solutions guarantee the metrological traceability of your measurement chain and are ideal for regulated industries. Traceability is ensured by the certifications of UNI CEI EN ISO/IEC 17025 accredited external calibration laboratories. The pH buffer solutions are DKD-DAkkS certified at the ZMK Zentrum für Messen und Kalibrieren. Conductivity standards are DANAK certified at the DFM Danish Institute of Fundamental Metrology. The Certification Report in accordance with ISO 17034 is available on request.