Reagecon's Chemical Oxygen Demand (COD) vials 0-15,000 mg/l can be used in conjunction with the Aqualytic PC Spectro®, Aqualytic PC Compact Vario® and all Hach® Spectrophotometers that accept 16mm vials. A comparative study of the performance of Reagecon COD vials compared to Hach® COD vials has been published, see Scientific Publications