COD digestion tube supplier

When using COD test tubes, we usually inject the sample to be tested into the test tube and shake the tube vigorously to suspend all the sediment. Remove the cap of the COD test tube and add 2 mL of sample using a pipette.

COD testing is a good better indicator of organic pollutants in industrial wastewater containing cyanides and heavy metals. For any requirements about COD Tubes, please tell me.
Product name: COD Tubes without Logo
Size: 16*100mm
Application: Water analysis
Material: Borosilicate 3.3 Glass
Melting point: -7℃
Certificate: ISO9001