Annoying high pitch noise generator by 555

This is a simple high pitch noise generator circuit. It has a timer oscillator with a frequency variable from 15khz – 30khz.
The circuit can be mounted in a plastic box like I have done. The good thing about high frequency sounds is that it is very hard to find where they are coming from. Also, the noise is very annoying and irritating. The crystal speaker is the creamy coloured thing at the bottom of the photo on the left.

Read More Source:http://www.geocities.com/electronics3456/highpitch.html
Thank you.

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