Commercial Inine dual TDS meter (monitor) This high quality inline dual TDS monitor is distributed by Filter Direct Co. Model: DM-2 FEATURES Highly efficient and accurate due to its advanced microprocessor technology. Displays TDS levels of the Feed Water and Product Water with in & out electrode probes. Auto-Off function conserves battery power. The unit shuts off automatically after 3 minutes (new version). Dual Range - Measures from 0-999 ppm, with a resolution of 1 ppm. From 1000 to 9990 ppm, the resolution is in 10 ppm increments, indicated by a blinking 'x10' image. Factory Calibrated: our meters are calibrated with a 342 ppm NaCl solution. Meters can be recalibrated with a mini-screwdriver. Comes equipped with 1/4 inch John Guest Quick-Connect T-fittings as shown. Also available with 3/8" fittings. Installs quickly and easily. Differences from the DM-1: Designed for commercial/industrial applications. Stronger, water-resistant casing. Calibration can be done individually or simultaneously on each line. Improved design, including an extra large, easy-to-read LCD display. Longer, waterproof, shielded cables. Variable mounting bracket SPECIFICATIONS Range: 0-9990 ppm Accuracy: ±2% Cable Length: 46" (including sensor) Calibration: Factory calibrated to NaCl 342 ppm. Re-calibration can be done separately for each line, or simultaneously for both. Power source: 2 AAA batteries (included) Battery life: over 1000 hours of continuous use Size: 11.6 x 6.8 x1.8 cm (4.6 x 2.6 x .7in.) Weight: 201.3 g (7.1 oz.) Measure the tap water coming in vs. the purified water going out of your system at any time. Use the meter to determine when the filters need to be changed. Install on industrial systems such as car washes, window washing, manufacturing, and food processing.