HORIBA Laqua Twin Nitrate Meter NO3-11 - Accurate Handheld Tester for Plant SapYour lab in a pocket HORIBA's unique NO3 11 compact nitrate meter integrates the electrode, display and sample container to enable simple, effective on site testing by direct measurement from a single drop. Since only a small sample is required, the meter is very suitable for measuring plant sap, giving an accurate picture of what is actually happening in a growing plant. In addition to NO3, the Laqua Twin range includes pH, EC, Na, K and Ca meters.