It's a logo of a microphone. The microphone is the old style that radio announcers of the thirties might have used. There is a slash over the microphone that would indicate that a microphone is either not available or is not allowed for use.
This Mute Unmute icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 5,700 icons, all in the same style and quality.