Indicator for an aeronautical Outer <a href="https://en.wikipedia.org/wiki/Marker_beacon" class="extiw" title="w:Marker beacon">w:Marker beacon</a>.
<a href="//commons.wikimedia.org/wiki/User:Denelson83" title="User:Denelson83">Denelson83</a>
<span class="int-own-work" lang="en">Own work</span>