EnvyPak Platinum Series protector pages are made from high-quality polypropylene and are acid-free. This page is made to fit standard mini binders or mini UniKeep binders.. Each Page holds four standard sized trading cards (3.5" x 2.5" inserts. They provide crystal clear, archival quality. Middle ring hole to outer ring holes are 2.75 inches center to center. Middle ring hole to closest ring holes are 1.575 inches center to center. These pages are perfect for storing Pokemon cards, baseball cards, football cards, or many other sport cards such as hockey, basketball, and soccer. Even Magic the Gathering cards will fit perfectly in these pages. Store and organize recipes, paper ephemera, photos, household information, or special scrapbook paper and embellishments. Like all EnvyPak products, these page protectors are made in the USA. This high-quality product is one of dozens of organizational tools available from EnvyPak, designed for ay standard mini binder or mini UniKeep binder. Each page is designed to make your life simpler when it comes to storing, organizing, protecting, or showing off your collections.