Viewsonics Professional Grade Lightning Surge Protector The VSGB1 provides full protection from surges that originate outside of your home Protects Plasma TVs, LCD TVs, Cable Modems, Media Centers,, HDTV, Video On-Demand, DVRs,VoIP Routers (Internet Phone service) and MORE! Easy to install - just place it into your cable line where the cable enters the house, and as always, ground your surge protector. We include instructions with each purchase. Designed For Broadband Applications - Transparent To Analog/Digital Bi-directional Signals Provides Lightning Surge Protection - Improves Broadband Reliability And Reduces Service Outages