System Sensor S241575 Category : System Sensor This alarm is a red SpectrAlert Classic remote strobe. Brand System SensorModel S241575Manufacturer System SensorType Alarm (Strobe)
System Sensor 4WT-B Category : System SensorThis 4-wire smoke detector also has a thermal heat sensor.
Wheelock 7002T-24 Category : WheelockEach 7002T-24 has a somewhat different pitch, so I’ve kept several that sound different from each other.