Product review (4 stars): Easily installed by anyone
This product is pretty basic.  Like others have observed, it does have thousands (maybe millions) of small perforations along it's entire length.  Also, it's not something that will withstand any pressure from the sides or from above due to something weighty being placed over it.  It's meant to be stretched out and left along with no constraining conditions.  It's just the way it's made.  If you can deal with that, it's easy to work with and quick to install in a variety of circumstances.