*This item is designed for cable network system installation and network technician to diagnostic network problem. *Wire finding is a major unique function where other cable checkers do not have it, it can locate up to 3000m long wire or cable even in a complex PC network or telephone system. *It also has a built-in LAN cable mapping function, to quickly diagnostic LAN cable condition and to identify fault point or broken connection. *Bright red LED torch and External Earphone support is value added function to enable service technician to work conveniently and comfortably in dark and noisy environment. package content: 1 x Emitter 1 x Receiver 1 x Earphone 1 x RJ45 Network Cable 1 x RJ11 Network Cable 1 x Color Box 1 x Toolkit 2 x 9V Battery 1 x User Manual