This is a Advertisement Page Filled icon. We've made it in iOS style, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 13,000 icons, all in the same style and quality.
The object is a box with a line across the top so that it is two spaces with the one on top being very narrow. There are three dots on the left side of the top portion. There is an arrow starting at the bottom left corner of the large portion of the box and it points diagonally to the top right corner of the box.