Introducing the first ever OPP trading card sleeves brought to the industry by ComicProLine. OPP (Oriented polypropylene) is a much more clear version of your standard polypropylene sleeves that you will find any other big name selling providing their customers. The difference in clarity between our premium OPP and the standard polypropylene is so easily noticeable. Get your premium card sleeves today at the best price offered by ComicProLine!