These are materials which, after drying under the specified conditions, are recommended for use as primary standards in the standardization of volumetric solutions. The following are recommended for use as primary standards.
| 1x | Pt-Co/ Hazen 200 Colour Reference Standard | EUR 89.00 |
| 1x | Отстъпка за безхартиено копие на Сертификат за анализ | EUR -1.00 |