They come by the names of Rife Generator, REM SuperPro Generator, PERL or Beam Ray, and are sold by a variety of commercial sources for up to $5000 per unit. The claim is that these instruments produce a specific "Mortal Oscillation Rate" that can kill cancer cells or infecting organisms without harming the surrounding tissue. You can get more information and links from this Wikipedia entry.
While conducting a Radio-Canada Zone Libre investigation on the alternative medicine industry, Luc Chartrand (in the blue shirt) and Germain Thibault (green shirt) were told that Rife Generators could also be used to cure infections caused by the fungal pathogen Candida albicans.
They already had access to a Rife Generator, courtesy of a local teacher (in the white shirt) who had acquired it in the hope of curing his son’s brain tumor. Since my lab does research on Candida, we developped a series of experiments designed to test whether this instrument can affect the viability of this fungi.
Source and all about the experience : http://www.digitalapoptosis.com/archives/science/001077.html