C-Line Artist Trading Card Holders Page Protectors with 10 Pages. Use the Trading Card Holders Page Protectors for your pocket-style pages or anything else that you can think of! These protectors will give you archival quality, acid-free protection for your ATC projects. High quality polypropylene that won't yellow with age. These crystal clear holders are by C-Line and measure 9 in. x 11 1/2 in. each and fit perfectly into a standard 3 ring A4 binder. They feature nine openings each opening measures 2 1/2 in. x 3 1/2 in. Each package includes ten card holders that are perfect for your memory book binder.