Kepo piezo transducers 15 to 35hz kepo kps g4210 1021 the kepo piezo transducer 1535hz is able to generate an audible siren tone when energised by a 9vdc rated voltage and 612vdc operating voltage outputs of up to 98db at 9vdc30cm can be achieved suitable for use in professional commercial and industrial applications kepo kps g4210 1021 piezo transducer 15 35hz 418mm