Features This Air Ion Tester is designed for test high level concentration of negative or positive air ion This instrument can be used to determine whether the negative ion polarity produced by air negative ion generator or air purifier is correct, and the concentration of ion concentration is estimated With it you can estimate whether the air ion generator or air purifier is working in good state Simple and small design, easy to carry, very easy to hang as a necklace Measuring range:10000 --- 19,990,000(ions/cc) Usage: 1. Switch to the "ON" position. 2. keeping the thumb and the square in front of the sheet metal, the metal plate toward the back of the air tested negative ion generator, and tested the closer air anion generator tester readings higher, whereas smaller. Therefore, to ensure the accuracy of the measurement results, leave the meter and test negative ion generator to maintain an appropriate distance. 3. the measurement process, do not touch the metal piece to the back of the instrument, otherwise it would be inaccurate readings. 4. If the reading is not preceded by the measurement symbol is measured positive ions, if the display "-" is negative ion surface. 5. To re-measure should first turn off the power, then restart it. Specification: Power supply: 2 x 1.5V LR44 button battery(built-in) LCD Display: Max reading of 1999 Test range is between 1x10000 to 1999x10000 ions/cc Resolution:1x10000 ions/cc Dimensions: 8 x 3 x 1.3cm/3.15 x 1.18 x 0.51inch Weight: 89g Note: 1. This instrument is a-high impedance measuring meter, it must pay attention to moisture when using and collecting, if moisture appeared then testing is unstable, reading disorder and other problems, then the available hair dryer or drying in the sun. 2. When the battery runs low battery symbol appears, it should open the back cover to replace the battery with the specifications and attention battery polarity. 3. If you need to get a more accurate ion content or measured ion content in the environment less than 10,000 (ions / cc) of the following, choose other anion detector please. Package Included: 1x Air Ion Tester 1 x Blue wrist strap Package List