Shop System Sensor Wired Horn Strobes at GeoArm Security. Browse hardwired LED, wall-mount, ceiling-mount, indoor, outdoor, weatherproof, and multi-candela fire alarm horn strobes designed to provide reliable audible and visual notifications for compatible fire alarm systems. System Sensor-compatible wired horn strobes support fire alarm systems eligible for GeoArm 24/7 professional UL-listed central station monitoring with no long-term contract.