Not that you asked, but are you going to be pulling air with a carbon filter in between the fan and the fixture? If no, the cap valuline 6" is a fine choice for a straight run duct to vent configuration. If yes, I would suggest the Can-Fan brand high output 6" (if it is a Can Filter brand 6" in between, it would cause a static pressure drop that a cap valuline doesn't handle as well) or at the least a grey Vortex brand 6" ( if it is a smaller carbon filter than the Can Fan brand). Just want to make sure you don't buy something that under performs if a carbon filter ever goes inline, unless of course you already ruled a filter out of the equation.