Nutrafin’s Nitrite Test (0.0 - 3.3 mg/L) measures the nitrite levels in fresh or saltwater aquariums. Nitrite should be tested on a weekly basis, as it is a toxic and potentially lethal nitrogen compound for fish. The kit provides up to 75 tests and includes: One 16 mL (0.5 fl oz) Bottle of Nitrite reagent # 1 One 10 mL (0.3 fl oz) Bottle of Nitrite reagent # 2 One Glass test tube with cap One Pipette One Lab base One Instruction booklet