Notes: This is an addressable smoke detector, more specifically a smoke sensor. The difference between the two is that a detector is used on non-addressable systems and detects conditions and decides whether or not to initiate an alarm. A sensor is used on an addressable system and simply detects air conditions and reports the data back to the control panel and it is the control panel's decision as to whether or not to initiate an alarm by comparing the data levels reported to the normal levels programmed into the control panel. The base seen pictured is model # SIGA-SB. The device address is set electronically via EST programming. There are two LEDs on this device. The green LED flashes to indicate power and polling status, the red LED flashes when in alarm. This sensor and base are only compatible with addressable EST control panels.