In article ,
Phisherman wrote:

I'm looking for a decent quality inline fan that will move air through
a 4" pipe, 30 feet long, but at a low CFM rate, perhaps 10 cfm. All
of the bath fans I've seen are 50 cfm or more or the variable speed DC
fans that are somewhat expensive ( $200).

McMaster Carr has a good selection of small fans. Check their electronic
equipment cooling fans. As low as 1.5 CFM if you have DC available.