Hydrofarm 4" Active Air Backdraft Damper - High Performance HVAC Ventilation for Grow Tents, Hydroponics & Indoor Gardening Systems

When I replaced the vent fan from our original Master Bath Heater/Vent/Light Assembly (installed 4" Duct Fan Assembly as replacement), I found the original plastic damper slammed close. I removed the plastic flapper valve type damper and replaced with this metal unit. Installed in less than 5 minutes and it works superbly! The rubber seal beats the heck out of the original plastic flapper! No back draft at all!It's junk, definitely not worth the money. The springs will go out any time now, because it hardly closes brand new. The axis pole that goes thru is missing an end washer, so that can slide out at anytime. There's only a small piece of foam barely glued on the inside for the damper to stop against, I had to re-glue mine fresh out the box. Spend the extra money and get one that'll hold up.Crapy junk do not buy they do not work this company selling them Sux as well.... JUNK JUNK JUNK JunkArrived damaged. Replacement arrived damaged. Returned and bought from another.Added some weight to the outer edge of the damper so as to make sure that it fully closes when it is not being used. has been working just fine for about a year now with no problems.barely stays closed without wind. And has leak lieak clearly trough the middle of both flaps.Spring was kinda cheap gets held open foam was also kinda cheap on the perimeterNice product but spring is not strong enough to close back the flaps. Will have to modify it.Works well