My home is a split foyer. So it's always either too hot or too cold on the lower level. Elima-draft vent covers have allowed me to finally use this space and be comfortable in it after 18 years. I'm very happy I found this product.
Advantages: They are Magnetic so no tools are required.
After removing about a quart of condensed water from several of my attic A/C flex ducts this winter (and replacing them because of the mold growth), I knew I had to find a solution to keep moist warm air from the house from finding its way up into the attic ductwork. The Elima-Draft register covers were exactly what I needed. I actually considered making them myself before finding these and after buying them I can't say I'd do it any differently. They saved me a lot of construction time.
Advantages: Easy install with magnets. Close fit for vapor trapping. Insulated to keep cold in the attic and not the house. Clean looking. Two of the six covers I ordered were the wrong size (my fault, I didn't realize two of my registers were larger), Gadgetsgo promptly exchanged them.