precipitator and acoustic cleaners, images donated by <a rel="nofollow" class="external text" href="http://www.primasonics.com">Primasonics</a>
No machine-readable author provided. <a href="//commons.wikimedia.org/wiki/User:Collieman" title="User:Collieman">Collieman</a> assumed (based on copyright claims).
CC BY 2.5
No machine-readable source provided. Own work assumed (based on copyright claims).