Kepo piezo elements for audio transducers kepo ft 27t 40b1 471 the keno piezo element 500 o 4 05khz is a 27mm diameter piezo element with a 20000nf30nf capacitance that can be used for a small audio transducer such as a buzzer kepo ft 27t 40b1 471 piezo element 500 ohm 4 05 khz 27mm