CoZroom Digital TDS Meter, Pocket Size Water Quality TDS Pen Tester, Blue Accurate: Made of titanium alloy probe without magnetic interference from water so its of very high accuracy (2%) and exquisite sensor within 5 seconds to complete measurement Practical: Measurement range of 0-9990 ppm; working temperature of 0-60 degrees; can automatically convert value of indication into value of 25 degrees with automatic temperature compensation Convenient: Large screen has liquid crystal display for easy viewing; lightest and most portable TDS instrument in market so far so you can keep it in pocket, tool bag and take it out when you need to measure Energy Saving: 2 *CR1620 1.5 V button battery which can be used for more than 3 years; 10 minutes without operation, it will automatically shutdown Multifunction: Ideal for all water purification applications, wastewater regulation, aquaculture, hydroponics, and colloidal silver, etc.