The HANNA HI 770 Checker®HC is accurate and affordable. This portable handheld colorimeter features a resolution of 1 ppm (200 points) and ±2 ppm ±5% of reading accuracy. The contoured style of the HI 770 Checker®HC fit in your palm and pocket perfectly and the large LCD is easy to read. The auto shut off feature assures the battery life will not be drained if you forget to turn it off. The HI 770 Checker®HC is simple to use. First, zero the instrument with your water sample. Next, add the reagents in order, respecting all the indications. Last, place the vial into the Checker®HC, press the operational button for about 3 seconds and the display will show the countdown prior to the measurement or, alternatively, wait for 2 minutes after last reagent adding and press operational button. The Checker®HC displays concentration in ppm of Silica as SiO2. Order Information: HI 770 Checker®HC is supplied with sample cuvettes with caps (2 ea.), powder reagents for 6 tests, battery and instructions.