Bel-art f37915-0525 borosilicate glass 25ml automatic self zeroing burette, 500ml reservoir avoid outside contamination with this highly accurate closed system. Borosilicate glass burettes have white 0.1ml graduations and are mounted to a high-density polyethylene screw cap. Squeezing the flexible polyethylene bottle forces liquid into the burette. Built in overflow automatically drains excess liquid back into reservoir. The glass stopcock has a 2mm bore. Large, stable plastic base can be detached from reservoir. Accuracy of burette is within 1% of total volume. Graduation accuracy is class a.