KIMAX Brand Burets, Serialized and Certified, Class A, Three-Way PTFE Stopcock Each KIMAX precision bore buret has a permanent unique serial number and durable white enameled scale. Fill through the stopcock using 0.25"" I.D. flexible tubing. Stopcock [PS] 2. Manufactured according to ASTM E287 Class A requirements Ordering Information: Shipped complete with KIM-KAP* dust cap and Certificate of Graduation Accuracy. Shipped in NSTA approved packaging.