A <a href="https://en.wikipedia.org/wiki/magnetron" class="extiw" title="en:magnetron">magnetron</a> tube from an advertisement in a 1954 electronics magazine, shown in its mounting beween two horseshoe-shaped <a href="https://en.wikipedia.org/wiki/alnico" class="extiw" title="en:alnico">alnico</a> magnets.  The tube is embraced on each end between the pole-pieces of the magnets, which create a magnetic field along the axis of the tube.  The tube is a Raytheon RK6410, a fixed frequency, pulse power 2760-2850 MHz (X band), capable of 5 MW peak power.<br><br>
Alterations to image: cropped out rest of advertisement and rotated image to better angle.
Unknown author<span style="display: none;">Unknown author</span>
Retrieved June 15, 2014 from <a rel="nofollow" class="external text" href="http://www.americanradiohistory.com/Archive-Tele-Tech/Tele-Tech-1954-11.pdf"><i>Tele-Tech</i> magazine, Caldwell-Clements Inc., Bristol, Connecticut, Vol. 13, No. 11, November 1954, p. 123</a> on <a rel="nofollow" class="external text" href="http://www.americanradiohistory.com/">American Radio History</a> website