This is a speech bubble. The speech bubble is in the shape of a rectangle with rounded edges and a little comma on the bottom left that would point towards the speaker. Inside of the speech bubble are 3 circles in a horizontal line.
This SMS 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 16,000 icons, all in the same style and quality.