VeeGee Glassco class A burets w/PTFE stopcocks meet ASTM E-287 Class A specifications. Made from precision, uniform Schott Duran® true-bore tubing to ensure the stipulated capacity tolerances. These burets feature durable, permanent markings, fine, sharp lines, and large, easy-to-read numbers. Supplied with PFTE stopcocks to eliminate freezing and lubricant contamination and to provide a precision fit within the barrel. All sizes are supplied with a 2mm stopcock bore plug.