3M FS195 intumescent pipe collar <a href="//commons.wikimedia.org/wiki/Firestop" title="Firestop">firestop</a> device for plastic pipe penetration. The picture also shows and <a href="//commons.wikimedia.org/wiki/Copper" title="Copper">copper</a> pipe and pipe hangers.
<a href="//commons.wikimedia.org/wiki/User:Achim_Hering" title="User:Achim Hering">Achim Hering</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>