<https://americansecuritytoday.com/covert-perimeter-sensors-for-next-generation-intrusion-detection/#primaryimage>
<http://schema.org/caption>
"Learn how the Terrain Defender TD100™ utilizes RF energy formed between two parallel coaxial cables to transmit and receive energy creating a static protection field."
<https://americansecuritytoday.com/covert-perimeter-sensors-for-next-generation-intrusion-detection/>