System Sensor HGWL-LF — Low Frequency Compact Horn
The System Sensor HGWL-LF is a low-frequency compact horn from the L-Series notification appliance family, engineered to meet modern fire-alarm and sleeping-area audibility requirements. It produces a 520 Hz ± 10 % low-frequency square-wave tone that aligns with NFPA 72 voice/alerting standards, making it especially effective at awakening occupants, including those with hearing impairments.
Key Features & Benefits
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Low-Frequency Tone (520 Hz): Designed to satisfy NFPA 72 2010/2013 low-frequency requirements for sleeping areas and other spaces where improved audibility is critical.
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Multiple Tone/Pattern Selection: Supports a variety of tone patterns, including Temporal 3, Temporal 4, Continuous, and Coded, via a rotary switch — versatile for many applications.
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Compact Wall Mount Design: Fits a standard single-gang electrical box with minimal intrusion, ideal for tight installations.
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Universal L-Series Mounting Plate: Plug-in design with a shorting spring enables wiring continuity testing before final installation, saving time and reducing ground-fault issues.
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Legacy Compatibility: Electrically compatible with legacy SpectrAlert and SpectrAlert Advance systems, simplifying upgrades or retrofit work.
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Tamper-Resistant Aesthetics: Sleek housing enhances interior appearance while meeting life-safety signage expectations.
- Operating Environment: Indoor use (typical 32 °F to 120 °F / 0 °C to 49 °C).


