-This Air Ion Tester is designed for test high level concentration of negative or positive air ion. <br />-It is effective to test the electric charge on the surface of textile by strict. <br />-With it you can estimate whether the air ion generator or air purifier is working in good state. <br />-Simple and small design， easy to carry，very easy to hang as a necklace<br />-Test the textile or cloth， judge the ion's polarity and concentration<br />-The reading of the tester is correlative to the air ion concentration， but not exactly the number of it. In factor， this tester can only provide you a rough measurement to the air ion source. Please don't take it as an precision instrument.<br />　<br />Specification:<br />Power supply: 1.5V x 2 LR44 button size battery <br />Dimensions:80mm(L) x 30mm(W) x 10mm(H) ;90g<br />LCD Display: Max reading of 1999<br />Test range is between 1x10000 to 1999x10000 ions/cc<br />Resolution:1x10000 ions/cc<br /><br />Attention:<br />1.Don't touch the rear square metal of the tester when testing<br />2.Please note that the colour may be a little different due to the effect of light<br /><br />Package included:<br />1*Air Ion Tester<br />4*LR44 buttons<br />1*Manual instruction<br />