A sign in a train station advising travellers that the public announcement system broadcasts with a hearing induction loop, to allow travellers with a hearing aid to tune into announcements directly with their hearing aid's receiver.
avlxyz
<a rel="nofollow" class="external free" href="https://www.flickr.com/photos/avlxyz/107168188/sizes/o/">https://www.flickr.com/photos/avlxyz/107168188/sizes/o/</a>