DiST 1 Waterproof Pocket TDS Meter (0-2000 ppm) DiST 1 HI98301 is a pocket tester for measuring TDS (Total Dissolved Solids) low range, which can measure up to 2000 ppm (mg/l). DiST 1 is rugged and reliable, ideal for both laboratory and field use. This new instrument is less than 2 cm thick, is ergonomic and comfortable to hold. DiST 1 is simple to use because it has only 2 buttons: one for turning on and off; the other for the calibration function. - Multi-level display - External temperature probe for quick response - Two operation buttons