[CR]Is this really only a chain tensioner?

(Example: Production Builders:Teledyne)

From: "The Maaslands" <TheMaaslands@comcast.net>
To: "CR" <Classicrendezvous@bikelist.org>
Date: Fri, 20 Oct 2006 18:47:44 -0400
Subject: [CR]Is this really only a chain tensioner?

http://cgi.ebay.fr/piece-pour-velo-ancien-neuf_W0QQitemZ290041785592

The seller says this is a chain tensioner, is it not perhaps something mre than that? Perhaps some type of derailleur?

Steven Maasland
Moorestown, NJ
USA