Free sample COD digestion reagent vials for water Free sample COD digestion reagent vials for water analysis from Europe COD Reagent Vials, 25 Tests, High Range, 0-1500 ppm CHEMetrics Mercury-free COD Reagent Vials, 0-1500 ppm (High Range HR), 25 vials, K-7361S Test MethodDichromate Reactor Digestion Includes25 vials (everything needed to perform up to 24 tests except for distilled water)