Triplett LVPRO20 Low Voltage Pro TDR and Cable Fault Tester is the middle level version of this low voltage tester. This model includes basic cable testing including wire mapping, pass/fail, delay and skew just like the LVPRO10. This version adds the Length RLQ pack which allows for more precise length measurements and return loss quality testing. The Triplett LVPRO20 Low Voltage Pro TDR and Cable Fault Tester is fantastic for installation and maintenance of CAT5/6 cables, VoIP phone and IP cameras, Ethernet devices, CCTV Security Cameras, and overall IT and network management.