There are two seals that you need- one for the moving piece and one for
the opening.  Should be around 100$ for both.  The Bus Depot only had one
seal the last time i checked- about a year ago.
-M

Matthew Pollard             http://www.uidaho.edu/~poll7356
Dept. of Chemistry               http://www.chem.uidaho.edu
University of Idaho                   http://www.uidaho.edu