Kimble kimax diagonal bore burettes with ptfe stopcock used for general purpose titrations requiring traceable volumetric accuracy. Diagonal bore stopcock and a funnel top precision bore buret is permanently marked with an individual serial number and is traceable to nist standards supplied with a certificate of graduation accuracy supplied with a chemically-resistant, self-lubricating ptfe stopcock plug easy-to-read durable white ceramic enamel scale designed from astm specification e287, class a requirements manufactured to the specifications found in astm e694 calibrated to the accuracy requirements found in astm specification e542 manufactured from 33 expansion, low extractable borosilicate glass conforming to usp type i and astm e438, type i, class a requirements. Warning: this product can expose you to chemicals including tetrafluoroethylene, which are known to the state of california to cause cancer. Prop 65 warning