Simplex 4051 The DC-powered version of the Simplex 4050, which runs on AC power. Brand SimplexModel 4051Manufacturer Federal SignalType Alarm (Horn)
EST 882-2B Category : EST/EdwardsThis unit has an electronic horn rather than an electromechanical mechanism.
Space Age A32-BL-SFXC-TJ24D-HA24D+HA24D Category : Space Age ElectronicsI’m pretty sure that the horn on this unit is made by Space Age Electronics. Otherwise, it’s probably a Wheelock...