There's a big online sale of quality filters at this site (http://www.centuryoptics.com/). due to their facility move.

Great tip Charles. Now now I have an excuse to buy some filters for my Series 9 lens hood!

I'm a little confused. All i see is just a pdf list. They don't seem to sell online. or do they?

try this kevin:

http://www.centuryoptics.com/pdf/Filter_IR_Web.pdf

I just placed an order using the 800 number listed in their contacts page. Call it, select option 1 and you're connected to a direct sales person. Apparently they are taking orders today and won't be able to ship for a few days. Very helpful and GREAT prices. $30 ea for 82mm!!!