All BLAUBRAND® burettes, automatic burettes and bulb pipettes 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, USP individual certificate or DAkkS calibration certificate.BLAUBRAND® ETERNA, class AS, DE-M marking. AR-Glas®. DIN EN ISO 648. Calibrated to deliver (TD, »Ex«). Waiting time 5 s. Ring mark and inscriptions in amber stain.