Aijiren COD Test Tube is made of borosilicate glass, which can reduce pH changes and pollutants that may be leached from soda lime glass. The glass digestion test tube can be used for analysis at temperatures higher than 130 degrees Celsius. It is manufactured from laboratory storage for a variety of general purposes and can hold almost anything. The gasket is made of a PTFE silicon rubber gasket, which has strong sealing performance and can resist various chemical corrosion. The COD Test Tube is small in size and light in weight. It can be tested without any other laboratory equipment and technicians; it only takes 3-5 minutes to test a sample, without additional materials or instruments and is easy to operate.