Borosil® Reusable Heavy Duty Culture Tubes are constructed from low-extractable, mechanically strong borosilicate glass. Supplied w/ PTFE-lined Polypropylene Screw Caps, Borosil® Culture Tubes are easy to handle & seal. Round bottoms & ultra-high clarity. Ideal replacement for media & culture bottles. Borosil® Heavy Duty Culture Tubes w/ Round Bottoms are available from 5mL to 150mL. Also available in Light-Blocking Amber (Product Family 9901). In collaboration w/ Borosil Glass Works, Foxx Life Sciences is proud to bring the outstanding quality of Borosil® Type 3.3 Borosilicate glassware to North America for the first time. Manufactured from the same USP Type 1 borosilicate glass that North American scientists have come to trust, Borosil® Laboratory Glassware offers unparalleled mechanical strength, clarity, & reliability at competitive prices. & thanks to a unique annealing process, Borosil® Glassware is stress-free & incredibly resistant to thermal shock.