with high quality. For checking TDS/salt (NaCl) levels in freshwater aquariums, ponds, and water purification systems. Smart pen combines TDS, EC, and a temperature meter for improved accuracy. With automatic temperature compensation and a measuring range of 0-9999 ppm +/- 2%. 4 display modes: SHIFT button toggles between TDS - ppm & Celsius, EC - s/cm & Celsius, TDS - ppm & Fahrenheit, EC - s/cm & Fahrenheit. Lock function for easy reading and recording; press HOLD button then remove from test solution. The instrument automatically shuts down after 5 minutes of inactivity. Conductivity: 0 - 9999 s/cm TDS: 0 - 9999 ppm Temperature range: 0.1 - 80.0 °C / 32.0 - 176.0 °F Resolution: TDS: 1 ppm; EC: 1 s/cm Battery: 1 x 3.0V (CR2032) Accuracy: ±2% Color: White Material: Plastic Size: 152 x 30 x 14 mm Package Contents: 1 x TDS & EC Meter Only the above package content, other products are not included. Note: Lighting and different displays may cause slight color variations between the item and the image. Measurement error allowed is +/- 1-3 cm.