Boro 3.3. To DIN EN ISO 385. Calibrated to deliver (TD, Ex). Schellbach stripe. Available with interchangeable needle-valve stopcock with PTFE spindle (PTFE key in the intermediate stopcock) or interchangeable glass key (glass key in the intermediate stopcock). All BLAUBRAND® burettes are delivered with batch number and enclosed one batch certificate per pack. Also available with individual certificate on request, USP Individual certificate or DAkkS calibration certificate.