Honeywell Silent Knight SD505-DUCTR, Duct Smoke Detector w/ Housing & RelayCondition:* New Surplus Stock, In OEM Packaging. As Pictured.Additional Notes:* The SD505-DUCTR is an addressable duct smoke detector with a relay module and SD505-APS sensor pre-installed in a heavy duty housing. * The SD505-DUCTR is used for detecting smoke and products of combustion present in air moving through an HVAC air handling system.* When smoke is detected in a duct, the unit sends a signal to the IntelliKnight control panel, which, depending on programming and wiring, will proceed to turn off fans, blowers, and other devices.* Current: .55 mA (alarm and standby)* Air Velocity: 300 to 4000 fpm* Ambient Temperature: 32F to 120F (0C to 49C)* Humidity: 10% to 85% RH* Color: Gray Backbox With Clear CoverHoneywell, Silent Knight SD505-DUCTR