what size media bags should I get for a fluval 406?

[solchitlins]

ok, I'm buying the a 300 watt 5/8" hydor eth in-line heater, eheim 5/8" tubing and a master test kit from Big Al's.
I need to spend a couple more bucks for free shipping, anyone know what size media bags would work best in the fluval 406 baskets?
I'm filling them with seachem matrix