Siemens U-MHU-MCS I believe that this alarm is capable of doing multiple tones. Brand SiemensModel U-MHU-MCSManufacturer SiemensType Alarm (Horn/Strobe)
System Sensor MA-12/24L Category : System SensorIf I remember correctly, this sounder can be used for purposes other than fire protection.
Honeywell S465B Category : HoneywellThis is essentially a slightly modified-looking version of the Honyewell S464A with a two-stage option.