ABOUT DETAILS - The gain is norminal 30dB, the input impedance is nominal 100M Ohm, and please notice that wire needs one 9V Battery(NOT INCLUDED). MEASURING RANGE - Measurement categories include line , short circuit testing, clear/busy/ringing identification. Selectable continuous or variable tone generator CLAMP MODE - For non-terminal cables, clamp mode can be used for direct measurement, as well as for telephone and network line measurement. HIGH ACCURACY - With optional continuous or adjustable generator, the method is simple and the test results are accurate. AVOID SHORT CIRCUIT - Built-in speaker tube on the probe, insulation probe and built-in loudspeaker can effectively avoid short circuit of conductor and to use. Colour:Gray-White Material:Plastic + Metal Package Contents: 1x wire 1x connector 1x accessories 1x canvas bag 1x English manual Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.