This easy-to-use, competitively priced tester is three tools in one - a Fault Locator, a Cable Wire Manager and a Tone Generator with SmartTone technology. Results appear as a distance reading rather than a waveform, so its perfect for technicians unfamiliar with Time Domain Reflectometery (TDR). From just ONE END of any two or more conductor cable you can measure up to 2500 feet. Easily find the distance to opens or shorts on electrical wire, telephone wire, security wire and coax. Voltage detection in the unit will immediately sound an alarm if you accidentally clip onto an energized pair, up to 250VAC.