The line locator has four functions:a) Cable locator - makes it easier to find cables in the wall and in cable ductsb) Continuity test - you can use the 8 test LEDs to determine whether there is a short circuit, cable break or dead switch, etcc) Telephone line tester - using the RJ11 telephone cable, an analog telephone line can be easily checked (line free, busy, dialing)d) Locating and checking LAN cablesWith powerful red LED light and external headphones, technicians can work well in dark and noisy environmentsFor testing telephone and LAN cables, checking the condition of LAN cables, finding and testing lines in electrical systems, continuity testing, low battery indication, line identification (open, short, the cross of LAN), line statusSpecification:Emitter: 10mAReceiver: 30mASignal transmission mode: digital signalSignal output level: 8Vp-pPowered by: 2 x 9V DC batteries (included)Color: as the pictures showPackage Weight: 313gPackage includes:1x wire tracker (emitter/receiver)1x cable with alligator clips1x RJ45 network cable1x RJ11 telephone cable1 x Earphone1x Packing box1x Instructions9V Batteries (included)Note:1. Please allow 1-3cm (0.4-1.18") difference due to manual measurement and slight color variation for different display setting.2. Due to the light and screen difference, the item's color may be slightly different from the pictures. Please understand.