Description: Piezo elements come in handy when you need to detect vibration or a knock. You can use these for tap or knock sensors pretty easily by reading the voltage on the output. They can also be used for a very small audio transducer such as a buzzer. * Resonant Frequency(kHz): 6.3 ±0.6kHz * Resonant Impedance (ohm):  1000 max * Capacitance (nF): 10.0 ±30% [1kHz]  To use it with your Arduino Board Click Here Please note in datesheet the part number for this element is 7BB-20-6L0