Has anyone used this type of fan/blower

I'm just wondering how loud this fan would run....or how loud squirrel fans in the 250 cfm range are....trying to maintain stealth operation

is that the 4 inch or 6 inch inline duct fan? i have the 6 inch model pulling air through an elf carbon filter. its a little on the noisy side, but for 30 bucks its not a bad choice at all.

I have a 6" duct fan that goes into a homemade filter. Its a little noisy coming out of the filter so I took a thick blanket and covered the filter. Now I can barely hear it and it still gets good airflow.

i bought same fan but 5 inch,wasnt impressed atall,could be the filter im trying it in but the thing wont even push open a dryer vent,the kind with hinges.somewhere on the box or site it says(110 cfm free air and 225 cfm boosted air)for the five inch.6 inch would be,125 free air cfm and 250 boosted air cfm,not sure what that means,but my fan seemed more like 110 then 225 cfm,