Tail section of a <a href="//commons.wikimedia.org/wiki/Category:Robin_DR300" title="Category:Robin DR300">Robin DR300</a>. The device mounted under the fuselage keeps the rope used for aerotowing. The rope has not been used for a longer time, so the rings at the end of it are rusted.
<a href="//commons.wikimedia.org/wiki/User:El_Grafo" title="User:El Grafo">El Grafo</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>