This is the Directed 504D Stinger Doubleguard shock sensor. It is the most accurate shock sensor for vehicle alarm systems available on the market today.
The most effective protection against shock/impact. Uses patented electromagnetic technology to eliminate mechanical parts. Two outputs are provided. The first offers a Warn Away response on light impact and the second instantly triggers the alarm on hard impact. Draws less than 1mA. Includes the plug-in harness for all alarms with the standard 4 pin sensor input plug.