KIMAX Brand Burets, Automatic Self-Zeroing, Class B, Three-Way PTFE Stopcock. Reliable KIMAX borosilicate construction with durable black enamel graduations. Side fill and overflow both accept 1/4"" flexible tubing. Filling is through stopcock. Calibrated from the tip of the overflow tube to deliver volume indicated. Manufactured according to ASTM E287 Class B requirements. Ordering Information: Shipped in NSTA approved packaging.