Just a word of warning about these devices that use foam in the interior (There are others with fire blankets, glass fibers or ceramics are okay.) Make sure these devices are further downrange of your exhaust setup. I’d say 8 or more ft. In some materials and throws a lot of embers during deep cuts will ignite the foam.
This is not an official Gowforge recommendation. This is a been there done that and it sucked word of warning.
Best solution is to use 4" insulated ducting. Make sure that the duct is the aluminized interior duct, not plastic. If you can not find that type. With a pair of gloves careful remove the plastic ducting and replace it with the one that came with your unit. This will cut the high pitch whine from the exhaust fan.