Product review (5 stars): Watch a YouTube video before attempting to install this.
Watch a YouTube video for installation tips.  You need to let this set out for a couple of days out of the box in a warmish place or use a hair dryer to get it to expand.  It is easy to install. If you have the right size and it seems like it does not fit perfectly at first, give it a day or two and you will get a tight seal.