The detector Sperry(TM) is designed to trace a variety of non current-carrying wires and cables. Each unit comes with a transmitter and a receiver. Under perfect conditions, the receiver will function up to 12'' from the wire being trace. The results may vary depending on different factors such as the type of insulation, the proximity of other wiring harnesses. This is normal and applies to all tracking devices. This product is covered by a 1-year warranty.