Rundprisma zur Vermessung.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/70981241@N00">Kecko</a> from Rural area of Eastern Switzerland
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/kecko/5562048512/">Surveying Prism Reflector</a>