The most common size for index cards in North America and UK is 3 by 5 inches (76. 2 by 127. 0 mm), hence the common name 3-by-5 card. Other sizes widely available include 4 by 6 inches (101. 6 by 152. 4 mm), 5 by 8 inches (127. 0 by 203. 2 mm) and ISO-size A7 (74 by 105 mm or 2. 9 by 4. 1 in). Cards are available in blank, ruled and grid styles in a variety of colors. Special divider cards with protruding tabs and a variety of cases and trays to hold the cards are also sold by stationers and office product companies. They are part of standard stationery and office supplies all around the globe.