Strathmore Artist Trading Card Sleeves - Protect and store your ATCs with these top-loading sleeves! Artist Trading Cards (ATCs) are miniature pieces of art that are traded around the world. Artists create, trade and collect art at organized swap events, either in person or online. The only official rule is that the trading card measures 2-1/2" x 3-1/2". Made of clear, rigid vinyl, these sleeves measure 3" x 4-1/2" making them ideal protecting mini artwork. Five sleeves per package.