This liquid-filled box and attached power supply are used for <a href="https://en.wikipedia.org/wiki/gel_electrophoresis" class="extiw" title="wikipedia:gel electrophoresis">gel electrophoresis</a>.
<a href="//commons.wikimedia.org/wiki/User:JVinocur" title="User:JVinocur">Jeffrey M. Vinocur</a>
CC BY 2.5
<span class="int-own-work" lang="en">Own work</span>