A warning beep is signaled when someone is within the vicinity of the vehicle. After a set amount of warning beeps has been signaled, the car alarm will sound. Single Adjust means you can adjust the sensitivity for exterior. Provides exterior zones of protection for the vehicle. When the exterior zone is penetrated a pre-warn signal is generated and sent to the security system's pre-warn input. Scytek Single Zone Motion Sensor For Car Alarm Proximity Sensor Motorcycle MS

This listing includes :
(1) Scytek Single Zone Motion Sensor MS

Single Zone Single Adjust Microwave Motion Radar Sensor Model: MS

A warning beep is signaled when someone is within the vicinity of the vehicle. After a set amount of warning beeps has been signaled, the car alarm will sound. Single Adjust means you can adjust the sensitivity for either exterior OR interior. Provides exterior zones of protection for the vehicle. When the exterior zone is penetrated a pre-warn signal is generated and sent to the security system's pre-warn input. When the interior zone is violated, the system immediately triggers a full alarm siren.

This is from Scytek and for Scytek But, Can be hard-wired to a negative instant trigger sensor input on any alarm Brand.