Inside of a NuTone K-22 model door chime, with wires leading into the chime.
<a href="//commons.wikimedia.org/w/index.php?title=User:Decreasing_volume&amp;action=edit&amp;redlink=1" class="new" title="User:Decreasing volume (page does not exist)">Decreasing volume</a>
<span class="int-own-work" lang="en">Own work</span>