Our Knock Sensor has a piece of piezoelectric ceramic inside. 

When you purchase an knock sensor, always ask seller if the piezoelectric ceramic is included.  Each of our products has a piece of  piezoelectric ceramic inside.  When the Knock happens, it will warn the ECU (Engine Control Unit). The ECU will then delay the ignition timing.   Without this piezoelectric ceramic, The ECU has noway to know the "knock" has happened.   It keeps on advancing the ignition timing. which will cause the temperature to be increased. In the end, the high temperature will damage the pistons.

This Knock Sensor, made by a reputable company in Taiwan, as original equipment or replacement of OEM, to worldwide automobile manufacturers.  Please verify your vehicle on our compatible chart above before your purchase.