BATCH CERTIFICATES All volumetric glassware material (measuring cylinders, flasks, pipettes and burettes) made on the same production date do have the same batch number. During the quality control process each piece is verified individually, dismissing those not fulfilling the maximum tolerances permitted. The batch certificate mention the average value obtained for all the pieces of the same batch, the standard deviation and the control date. This batch certificate can be downloaded free of charge at ‘Download certificates‘ section INDIVIDUAL CALIBRATION CERTIFICATE Glassware with an individual certificate do have an individual serial number added to the batch number. They are delivered with a certificate showing the real volume of this particular flask.