Siemens U-MHST-MCS I believe that this alarm has the ability to produce multiple tones. Brand SiemensModel U-MHST-MCSManufacturer SiemensType Alarm (Horn/Strobe)
Simplex 4904-9053 Category : SimplexI accidentally bought this particular unit not realizing I already had one. Oh well, happens.
Simplex 4901-9811 Category : SimplexThis particular alarm is actually capable of doing three different tones.