Thunderbolt
The Thunderbolt siren was a supercharged electromechanical siren produced by Federal Electric, which later became known as Federal Sign & Signal and Federal Signal. The Thunderbolt has seven chopper levels, or voltage settings, that allow the pitch to be adjusted on the chopper, the Thunderbolt can come in three port ratios, 5 Port, 4/5 Port, and 5/6 Port.
Thunderbolt 1000
The Thunderbolt 1000 is a Single-tone supercharged siren that is part of the Thunderbolt Siren series. The Thunderbolt 1000 has a chopper that contains 5 ports.
Thunderbolt 1000T
Thunderbolt 1003
The Thunderbolt 1003 uses two solenoids that are attached to the upper portion of the siren to create a third, high-low signal, which can be used as a fire signal.