Greenlee 501 Tracker II Cable Locator Traces the path and determines the depth of wires and metallic pipes on active or dead systems without having to deactivate the system Lightweight receiver provides audible and visual indications of signal strength. Transmitter Frequency : 447.5 KHZ Transmitter output and receiver sensitivity are fully adjustable for maximum accuracy Transmitter offers three methods of connection direct, inductive coupler and inductive antenna High frequency transmitter provides range up to 4000-Feet and depths up to 7-Feet