I may have never even used these - I can't remember.  If I have, it was only once (decided I prefer bottles on the bent).  Purchased around June 2010.  Fits Rans and Bacchetta "Mesh Seats".  Bladder is the 3L Rapid Refill.  Check it out:
 
$60 - I don't want to sell the bag without the bladder - but will sell just the bladder if anyone is interested.
 
http://www.fastbacksystem.com/page16/page16.html
http://www.fastbacksystem.com/page34/page34.html