These reusable glass round bottom Test Tubes are made of 3.3 borosilicate glass to reduce pH changes and contaminants potentially leached from soda-lime glass. Deep-form threaded phenolic caps provided with Tubes are fabricated from a special formula resistant to the effects of temperature and steam in autoclaving. Glued-in, white rubber liner provides secure seal.

These reusable glass round bottom Test Tubes are made of 3.3 borosilicate glass to reduce pH changes and contaminants potentially leached from soda-lime glass. Deep-form threaded phenolic caps provided with Tubes are fabricated from a special formula resistant to the effects of temperature and steam in autoclaving. Glued-in, white rubber liner provides secure seal.