MBL Sofnol pattern automatic zero burettes from Scilabware conform to ISO385. For water testing. Graduations are in blue enamel. With pinchclip, rubber tube, jet 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 20ml burette has a 1000ml reservoir bottle.