PYREX 27mL Test Tubes are made from special tubing for optimum wall thickness. Well annealed, resistant to heat and chemically stable; beaded rims are fire-polished. Tubes have white marking spot. Material: Borosilicate Glass Code 7740. Style: Plain Cylindrical Test Tube (No Graduations, No Cap, No Stopper). Capacity: 27mL. Length: 150mm (Approx). Outer Diameter: 18mm (Approx). Corning #: 9800-18.