Trailer Dog has several security systems on the market, all with one goal in mind - to deter thieves. All Trailer Dog Security Systems can work off of solar energy (with battery back-up), making it ideal for locations where electricity isn't available. When unauthorized activity is detected, units will sound two ear-piercing sirens, flash lights and even lock trailer brakes (if applicable). Often times, the siren and lights alone will be enough to make a thief run. But for additional peace-of-mind, G units come with real-time GPS tracking, cellular notifications and can be remotely controlled though the Internet.