Borosil Reusable Heavy Duty Test Tubes are constructed from mechanically strong, low-extractable borosilicate glass. Thick, uniform walls, excellent heat resistance & rounded bottoms mean these tubes can be reused without issue. Each tube is graduated in metric units & comes with a standard taper glass stopper. Borosil Reusable Heavy Duty Test Tubes with Graduations & Glass Stoppers are Avail. from 10mL (17mm x 160mm) to 100mL (34mm x 210mm). In collaboration with 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. And thanks to a unique annealing process, Borosil Glassware is stress-free and incredibly resistant to thermal shock.