1.Nutrient technical parameters: Stability: Absorbency of light drift <0.003 Repeatability: A (absorbency of light) < 0.005 Linearity errors: red light for Copper sulfate, and blue light for potassium bichromate <3.0% Sensitivity: Red light ≥4.5×10^-3, Blue light ≥3.17×10^-3 Wavelength range: Red light 620±4nm; Blue light 440±4nm Anti-knocking performance: qualified ( Attention: above technical parameters all exceed national standards) 2.PH Technical parameters: Testing range: 1-14 Error: ±0.5 3.Salinity Technical parameters Testing range: 0.01%-1.00% Relative error: ±0.5 4.Soil Moisture Technical parameters: Moisture unit: %(m³/m³) Moisture content rate testing range: 0-100% Accuracy:±2% Measurement range: 0.01%-1.00% Relative error: ±5% 5. Power: AC: 220V-240V, 50Hz DC: 18v, 5W (built-in) With a software CD is provided as well. Be able to store, print, and send the data remotely by computer. Instruction Manual