Vintage industrial machine age electric fire alarm bell. This large mid-century fire alarm would probably have been used in a factory or industrial setting, or perhaps a school or other large public building. This alarm still has the old red paint on the steel bell and is marked on the name tag "Alarm Device Mfg Co. - Syosset, L.I., N.Y.". It is also marked as model "AD8" and is rated for 6 volts DC (direct current). This fire alarm carries a US Patent number from 1950. This measures about 8" across the alarm bell and 5" square on the cast metal mounting. We hooked this to a 6 volt battery charger and it works.