HI9813-6 GROCHECK PORTABLE COMBO. pH/EC/TDS/Temp Meter with F.S.T. Technology New Technology to Check the Status of the Electrode Measures a Variety of Parameters with One Instrument Fast Response Probe HANNA instruments® developed new F.S.T. technology for the new HI 9813-6. With this special security system, if the meter encounters incorrect readings, the instrument doesn’t display values close to pH 7, but close to pH 4, making the problem clear. To allow maximum confidence in your measurements, the meter is equipped with two LEDs and a Check button. When pressing this button, after immersing the electrode in the proper solution, HI 50021P (Cal-Check solution), one of the LED’s will light up to indicate the status of the meter. The green LED (OK) indicates the probe is working correctly, while the red LED (C&C Clean & Cal) indicates the electrode needs attention. HI 9813-6 is supplied complete with pH/EC/TDS/T HI 1285-6 probe with 1 m cable, pH 7, 1.41 mS/cm and 1500 ppm calibration solution (20 mL each), cleaning solution 2 pcs), HI 50021 test solution (2 pcs), blue protective case, battery and instructions.