Precision bore tubing is used these 10mL-100mL Class A PYREX® burets to assure accuracy between any two points. The capacity tolerance on these burets is established by ASTM E-287 and is calibrated in accordance with ASTM E542. Each buret is individually serialized and supplied with a Certificate of Identification and Capacity, traceable to NIST standards. Durable colored graduations are sharply defined and easy to read. Carefully ground Standard Taper stopcock gives precise control. All sizes furnished with a 2mm bore stopcock plug. For replacement PYREX® stopcocks, see No. 7680. For replacement retaining clips, see No. 7280. Each buret is supplied with a dust cover.