There are a several choices when it comes to termination covers. Plastic or metal; louvered or single-dampere; hooded or flush. Louvered models can have two, three, or four louvers. If metal, they can be paintable, galvanized, or pre-finished. Plastic models can consist of the standard cover or have multiple pieces which comprise act as flashing. Sometimes a termination cover will be installed over the siding, flashed around the siding, or with part of it under the siding. Plastic models can also dramatically vary in quality, leading lower quality models to disintegrate or break easily. There is even a model that has two single-dampers. one on top of the other, to deter bird entry.
We prefer to install metal covers because they tend to last far longer than their plastic counterparts. By far and away, the most popular model we install is this:
Why do we like it so much? It is the most attractive and efficient cover on the market (that we are aware of, at least--and we are aware of most of them!). Also, it is more easily cleanable than other metal models, ensuring the damper remains functional. Perhaps most importantly, it has a couple layers of bird resistance built into it so as to thwart off avian entry. (However, there is also a matching bird guard to definitely ensure that they stay out!)