CPI International, Inc. is the holding company for Communications & Power Industries, the largest manufacturer and rebuilder of electron devices (primarily vacuum tube

Vacuum tube

In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...

s) in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. C&PI was founded in 1995 http://www.secinfo.com/dsVQy.a391.htm when Varian Associates

Varian Associates

Varian Associates was one of the first high-tech companies in Silicon Valley. It was founded in 1948 by Russell H. and Sigurd F. Varian, William Webster Hansen, and Edward Ginzton to sell the klystron, the first tube which could generate electromagnetic waves at microwave frequencies, and other...

 sold its electron-device business (the original business of its founders) to concentrate on medical systems. Its major subsidiaries include Eimac

Eimac

Eimac is a trade mark of Eimac Products, part of the Microwave Power Products Division of Communications & Power Industries. It produces vacuum tubes for radio frequency applications such as broadcast and radar transmitters.-History:...

 (which manufactures new vacuum tubes for the broadcasting, radar, medical systems, and other applications), Econco (a vacuum-tube rebuilder), and Beverly Microwave Systems. CPI International made its initial public offering

Initial public offering

An initial public offering or stock market launch, is the first sale of stock by a private company to the public. It can be used by either small or large companies to raise expansion capital and become publicly traded enterprises...

in April, 2006.