Searching for a Free Knockout Font

[DeFlorio, Dominick]

Hello Framers,
 
I'm looking for a free, sans serif, knockout font, with a similar look
as the Arial font.
 
I'm trying to get past using two different font attributes (color: white
or black) for callouts on dark, light and mottled backgrounds.  I
noticed in an old Troy-Bilt manual, that they successfully used a
knockout font on all types of backgrounds.  With this in mind, I
searched for a font with similar attributes but couldn't find a free
one.  Any ideas? 
 
Dominick A. DeFlorio
Senior Technical Writer
Plug Power, Inc.
968 Albany-Shaker Road
Latham, NY 12110
(518) 738-0389