... ,24V, 48V (2) Size: 2inch -12inch KCB series fire alarm bell / Electric bellFeature:(1) Voltage: AC 12V, 24V,110V, 220V, 380V DC 12V ... , 24V, 48V(2) Specification: Model No. Diameter(mm)Alarm sound weight ... manufacture by OEM, welcome your kind enqiury. CB series fire alarm bell / Electric bell