These Sartorius Calibration Weights are sold individually with a choice of No Certificate, UKAS Accreditation, or with a Certificate of Calibration (NVLAP). Your choice of Certificates determine the price of your calibration weight. Class E1 weights intended to ensure traceability between national mass standards (with values derived from the International Prototype of the kilogram) and weights of class E2 and lower (ie F1, F2 ...). Class E1 weights or weight sets shall be accompanied by a calibration certificate.

What is OIML? In Europe the weight classification system adopted is that produced by the International Organization of Legal Metrology (OIML), known as document OIML Recommendation R 111. It describes the metrological aspects of reference standard weights with recommendations for seven classes of weights - from high quality reference standards at Class E1 to those used in industrial settings at Class M3.

What is UKAS? Accreditation by UKAS means that evaluators i.e. testing and calibration laboratories, certification and inspection bodies have been assessed against internationally recognised standards to demonstrate their competence, impartiality and performance capability. It is the ability to distinguish between a proven, competent evaluator that ensures that the selection of a laboratory, certification or inspection body is an informed choice and not a gamble. UKAS accreditation means the evaluator can show to its customer that it has been successful at meeting the requirements of international accreditation standards

What is NVLAP?
The National Voluntary Laboratory Accreditation Program (NVLAP). This program evaluates and accredits laboratories in their respective fields and ensures they meet ISO standards.