Inside a disassembled <a href="https://en.wikipedia.org/wiki/radar_speed_gun" class="extiw" title="en:radar speed gun">radar speed gun</a>, used by police to measure the speed of cars.  The copper-colored cone is the <a href="https://en.wikipedia.org/wiki/horn_antenna" class="extiw" title="en:horn antenna">horn antenna</a> which emits the beam of <a href="https://en.wikipedia.org/wiki/microwave" class="extiw" title="en:microwave">microwaves</a>.  The small grey unit mounted at its apex is a 24GHz <a href="https://en.wikipedia.org/wiki/Gunn_diode" class="extiw" title="en:Gunn diode">Gunn diode</a> <a href="https://en.wikipedia.org/wiki/electronic_oscillator" class="extiw" title="en:electronic oscillator">oscillator</a> which generates the microwaves. The GaAs Gunn diode is mounted inside a resonant waveguide cavity diecast from <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Mazak_(alloy)&amp;redirect=no">Mazak</a> zinc aluminium alloy.
<ul><li>Original work: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/52365139@N05">Dennis van Zuijlekom</a> from Ermelo, The Netherlands</li>
<li>Derivative work: <a href="//commons.wikimedia.org/w/index.php?title=User:Chetvorno&amp;action=edit&amp;redlink=1" class="new" title="User:Chetvorno (page does not exist)">User:Chetvorno</a></li></ul>
CC BY-SA 2.0
<ul><li>Derivative of: <a href="//commons.wikimedia.org/wiki/File:Radar_Gun_Electronics.jpg" title="File:Radar Gun Electronics.jpg">Radar Gun Electronics.jpg</a></li>
<li>Original image: <a rel="nofollow" class="external text" href="https://www.flickr.com/photos/dvanzuijlekom/6650053867/">Radar Gun Electronics: Detail Shot</a> on Flickr.</li></ul>