Yeah hydrofarm makes those for the specific hoods, perfect fit. But i would start with just insulated ducting, then if u are still having issues then get the cover, there is some issues with the theory of those things. Of course this is easy to say but when you are cooking plants you have to fix things fast i know, i personally would use a bigger fan, as straight a run for the ducting as possible, and insulated ducting, should fix the heat issues.