10ml COD Digestion Screw Round Bottom Pyrex Borosilicate Glass Tube with Cap. Applicable instrument models: DR2700 spectrophotometer, DR890, series of multi-parameter water quality analysis, DR5000, DR6000 ultraviolet-visible spectrophotometer, DR2800, portable spectrophotometer, DR3900 desktop spectrophotometer, DR1010 COD. Cleaning instructions: