The 3" x 5¼" Top Bound Field-Flex books are made to ensure they will not fall apart in the field. They have a flexible cover that can withstand the harshest conditions. Each book contains 100 pages (50 perforated sheets) of Universal page pattern. The sheets are flush with the cover and the corners are rounded to improve durability. Since these books are top bound it gives you more writing space and they are easier to open.