Pyrex® Sofnol pattern automatic zero burettes from Scilabware conform to ISO385. For water testing. Graduations are in blue enamel. With GP rotaflo stopcock offering fine drop control when dispensing and polyethylene reservoir bottle. The burette is filled by squeezing the bottle. Once the bottle is released, excess liquid can drain back into the bottle until the burette is set to zero. The 25ml burette has a 1000ml reservoir bottle.