Extech DO600 Exstik II Dissolved Oxygen Meter adds versatility on measuring Dissolved Oxygen in laboratories or out in the field with a 16ft (5m) extension cable and probe weight guard for taking easy measurements in tanks or streams. With the Exstik II, oxygen level is displayed as % Saturation from 0 to 200.0% or Concentration from 0 to 20.00ppm (mg/L).