The image is of a notepad or calendar with the number thirteen. There are two little tabs at the top of a square which would be the binds for the notepad or calendar. The number 13 is just centered in the bigger part of the square sheet.
This Calendar 13 icon is a responsive icon. This means that it's optimized for four resolutions, from tiny 16x16 until highly detailed 80x80. The style comes from the latest Microsoft Office
, which makes it perfect for any Windows applications, in particular, those with ribbon toolbar control. Unlike other icon packs that have merely hundreds of icons, this monster icon pack contains 15,700 icons, all in the same style and quality.