System Sensor 4WT-B White 4-Wire Photoelectric i3 Series Smoke Detector with 135F Fixed Thermal Sensor combines advanced photoelectric smoke detection with a built-in 135°F fixed thermal sensor to provide reliable fire protection in commercial and residential applications. Its intelligent i3 Series design simplifies installation, testing, and maintenance while helping reduce nuisance alarms through advanced signal processing.

• Photoelectric smoke sensing combined with a 135°F fixed thermal sensor for enhanced fire detection performance
• 4-wire design with included mounting base supports flexible integration into conventional fire alarm systems
• Stop-Drop ’N Lock mounting mechanism allows quick installation and easy detector replacement
• Drift compensation and smoothing algorithms help minimize false alarms caused by dust and environmental changes
• Remote maintenance signaling, dual-color LED status indication, and simplified sensitivity testing streamline ongoing system maintenance