Manufactured from Type I, Class B borosilicate glass, each tube is heat-treated at temperatures exceeding 500°C (932°F) immediately before packing, which eliminates contamination, increases strength, and reduces breakage. Tubes exceed USP Type I specifications. Tubes feature well-rounded bottoms and fire-polished tops free of rough edges. Dimensional specifications of these tubes are rigidly controlled for reliable, uniform results. Tubes are clean-sealed in a convenient dispensing package to keep them free from dust and other particulate contamination. Tube 47729-566 is also known as a Durham tube.. Chemically inert. High heat tolerance. Uniform dimensions. . . VWR 47729-572 Culture Disposable Tube, 13mm OD, 9ml Volume, 100mm Length, Borosilicate Glass, Pack of 1000. Country of Origin : United States. Part Number : 1176K47CS. Pack of : 1000.