I waited over a year to review this item to make a proper review.  The plastic is of that of a grill cover or patio furniture cover.  The PVC frame that came with it didn't fit properly so my husband used a saw to modify it to be assembled correctly which was disappointing.  It doesn't keep any smell inside and is simply used to avoid making eye contact with your cat while they are using it.  I threw the bottom portion away since it was too much trouble to zipper the thing on and off when I did thorough cleaning.  Not a fan