1)electromagnetic type 2)safety alarm of short circuit,overload,over voltage,time limiting FW-MS290 motor siren is with horn and alarm sound in the fast speed. Specification:Voltage(V)1224110220Current(A)2.41.20.80.24db(A)1m113113113113Hz1150115011501150N/W(kg)0.95 guard against theft series type motor siren