Laura gives us the lowdown on the System Sensor DNR Duct Smoke Detector. Intelligent Non-Relay Photoelectric Low-Flow Duct Smoke Detector!
System Sensor DNR: https://firealarm.com/product/system-sensor-dnr/
System Sensor RTS151KEY: https://firealarm.com/product/system-sensor-rts151key/
Learn more about System Sensor Here.