Our Test Tubes are manufactured from low alkali type 3.3 borosilicate glass. It is virtually free of magnesia-lime zinc group and is free of arsenic and other heavy metals. The borosilicate glass is low expansion, and can be used for applications up to 500°C. Our glassware is clear and colorless, and shows no noticeable absorption in the visible region of the spectrum. The glassware is also highly resistant to water, neutral and acid solutions, concentrated acids and their mixtures as well as to chlorine, bromine, iodine, and organic matters. During extended periods or reactions and at temperatures above 100°C, its chemical resistance exceeds that of most metals and other materials. Our test tubes are able to withstand repeated sterilization.