Call of Cthulhu 7th Edition Keeper's Screen Pack - Rules of Play says:

The Call of Cthulhu Keeper Screen Pack is an great play aid for those running games of Call of Cthulhu 7th edition. The Keeper Screen is mounted on thick hardcover stock, folding out to 34 inches wide. One side, intended to face the players, portrays glorious artwork. The rear of the screen, the Keeper’s side, collects and summarizes important rules, statistics and charts, to assist the Keeper when running games.