System Sensor HGRL-LF L-Series Indoor Low Frequency Compact Sounder, Plain, Wall Mount, Red

Put occupant safety first with the System Sensor HGRL-LF L-Series indoor low-frequency sounder. Specifically engineered as a reliable audible notification appliance for fire and security monitoring, this wall-mount sounder delivers a 520 Hz ±10% square-wave tone shown to be more effective at waking occupants — including those with hearing loss — meeting NFPA 72 (2010/2013) and NFPA 720 (2012) low-frequency requirements. The compact red housing and plug-in design minimize backbox intrusion and speed installation, while the mounting plate shorting spring verifies wiring continuity before device installation to reduce call-backs. Field-selectable settings and rotary controls allow you to optimize current draw for diverse commercial or residential sleeping spaces. Electrically compatible with legacy SpectrAlert and SpectrAlert Advance devices and compatible with MDL3 sync modules, the HGRL-LF integrates smoothly into existing wired security, surveillance, and alarm systems powered at 33V DC. Ideal for hotels, multi-family housing, healthcare facilities, and retrofit projects — specify the HGRL-LF for dependable, code-compliant audible notification. Add it to your fire alarm and security monitoring setup today.

• Improves occupant safety with NFPA-compliant low-frequency (520 Hz ±10%) tones proven to wake sleeping or hearing-impaired individuals
• Easy, retrofit-friendly installation with plug-in design, mounting plate continuity check, and compatibility with legacy SpectrAlert systems
• Compact red wall-mount form factor minimizes intrusion into backbox while providing a clear, reliable audible alert for fire and security monitoring
• Field-selectable settings and rotary controls let you balance performance and current draw for varied commercial and residential applications
• Designed for dependable integration into wired security and fire alarm systems (33V DC input), reducing installation time and system downtime