50ml Schell Bach burette with blue graduations Accuracy as per DIN 12700, ISO 385. Class A - Capacity 50ml - Sub. Div. 0.10ml Tolerance ± 0.05ml Premium quality glass with white backing to provide maximum accuracy in measuring colorless fluids 31" in length This premium quality Schell Bach burette has a white backing to allow for the highest accuracy in measuring clear liquids. It measures 31" in length and has a PTFE stopcock for controlling the flow of liquids. Graduations are marked in blue for ease of reading.