Product review (5 stars): Buy this and keep the birds where they belong!
Our dryer stopped working.  Turns out birds had nested in our dryer vent, completely obstructing it.  We are lucky we didn't have a house fire. Directions are clear, very easy to install.  Extending the vent tubing inside the closure as described is an excellent idea and aids both fit and seal.  Vents lint without clogging.  I had one of the mesh covers and it clogged almost weekly - the plastic finally broke.  I recently read that the mesh sort of cover is unsafe for this very reason.  Now the birds are in the trees where they belong!