KoiMedic is specially designed to measure the delicate salt concentration in the pond. The tester can display measurement in percentage (%) or parts per thousand (ppt). The tester is easy to use and accurate. It is the best companion for Koi or fish requiring the tonic of salt to improve health. Advanced Features: Display reading in % or ppt. One touch calibration. TECHINICAL DATA Model: KoiMedic Units of measurement % ppt Range: 0.00 to 1.00% 0.0 to 10.0 ppt Resolution: 0.01% 0.1 ppt Accuracy: ± 0.03% ± 0.3 ppt Battery Type: 4 x 1.5V button cell (Alkaline A76 or equivalent) Battery Life: Approx. 150 hours Automatic Temperature Compensation: 0 to 50°C or 32 to 122°F Packaging Dimension Size (LxWxH): 185mm x 65mm x 25mm Packaging Weight: Approx. 135gm Product Dimension Size (LxWxH): 170mm x 32mm x 15mm Product Weight: Approx. 70gm