This appears to be a rectangle situated vertically. There is a vertical line inside the rectangle, going from the bottom left corner of the rectangle to the top right corner. There are two small triangles, one connected to the bottom left of the line and one connected to the top right end of the line.
Related to Screen Resolution Icon
Related icons are the icons with matching tags, as well as all mobile icons. All icons are in the same flat style. You can either download free PNG icons or buy SVG vectors