This is the Directed 504D Stinger DoubleGuard shock sensor. Most shock sensors rely on a moving part to detect an impact, and moving parts wear. The 504D uses patented electromagnetic technology instead, with nothing mechanical inside to go out of calibration or seize up. Dual stage. Two separate outputs: a warn-away response on light impact, which chirps and tells someone to step back, and a full alarm trigger on a hard strike. That distinction is what stops your alarm going off every time someone brushes past. Specifications Electromagnetic sensing, no mechanical parts Two outputs: warn away and full trigger Draws under 1 mA Plug-in harness included, fits alarms with the standard 4 pin sensor input Want tilt detection as well? See the Compustar FT-SHOCK-II, or the FT-DAS-II which adds glass break and movement too.
