BLAUBRAND®, Boro 3.3. DIN EN ISO 1042, DE-M marking. Calibrated to contain (TC, In). Marks and inscriptions in high contrast white enamel. All BLAUBRAND® volumetric flasks are supplied with a batch number and an accompanying batch certificate in the original packaging. On request, they are also available with an individual certificate or DAkkS calibration certificate. BLAUBRAND®, Boro 3.3. DIN EN ISO 1042, DE-M marking. Calibrated to contain (TC, In). Marks and inscriptions in high contrast white enamel. All BLAUBRAND® volumetric flasks are supplied with a batch number and an accompanying batch certificate in the original packaging. On request, they are also available with an individual certificate or DAkkS calibration certificate.