Ball turret from a Grumman TBF Avenger on display at the Intrepid Sea-Air-Space Museum in New York City
<a href="//commons.wikimedia.org/wiki/User:Chumash11" title="User:Chumash11">Rania al-Bahara</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>