Product review (4 stars): This works very well and allows your dryer to be ...
This works very well and allows your dryer to be placed relatively close to the back wall.  However, because it is solid it is more likely to pull out of either the dryer or wall connection.  We have now, hopefully, solved that by putting a firm piece of foam between the top part of the vent and the wall and the bottom part of the vent and the dryer.  This should lock the vent into place.  A sliced yoga block seems to fit perfectly.