Features This Air Ion Tester is designed for test high level concentration of negative or positive air ion.Can show positive and negative ion concentrations. 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.LCD display: display value units for the million, the maximum reading 1999. Simple and small design, easy to carry, very easy to hang as a necklace.Compact, easy to carry.For a variety of negative ion generator, air purifier, air conditioning, high concentration of the ion source to measure. Measuring range:10000 ‑‑‑ 19,990,000(ions/cc).Resolution: 10000 (ions / cc).The maximum value remains (AITP).LR44button battery is required(battery not included) Descriptions:This instrument is a qualitative product, rather than quantitative products, because of the accuracy, only suitable for testing values of negative ion air purifiers and negative ion generator, and there are certain floating customers, if you mind, choose others please, thanks.AIT (P) ion meter advantages:AIT (P) anion ion gauge is AIT gauge improved, it is the biggest difference between the AIT is the maximum value of the measured air ions remain on the display, it will give the instrument readings more stable, easy to read . Before each measurement to confirm the switch in the "off" position, when you start to make the instrument away from the object, so that its initial reading of zero or close to zero regulation and then slowly close the ion source. It displays the reading will remain until the power is turned off. Specification: Power supply: 2 x 1.5V LR44 button battery(built-in)LCD Display: Maximum reading of 1999 Test range is between 1x10000 to 1999x10000 ions/cc Resolution:1x10000 ions/ccDimensions: 8 x 3 x 1.3cm/3.15 x 1.18 x 0.51inchWeight: 89g Package Included: 1x Air Ion Tester1 x Blue wrist strap Note:The product has 2 built-in button batteries. In addition, four external button batteries are needed, but the four external batteries are not included. Package List