Directed 506T Audio Glass Break Sensor Features: Detects even quiet breaks: That might not trigger the shock sensor. Microphone and microprocessor: Detect tampering and breaking of vehicle's glass and analyze frequency, intensity and timing of intrusion sounds to eliminate false alarms. This Clifford product may require professional installation Owner's manual is included Compatible with Directed Electronics alarm systems Directed Electronics Viper Audio Glass Break Sensor is included; This product may require professional installation Type: Car Stereo Add-Ons